Translation of
Aimen, J. 1760. Recherches sur les progres et la cause
de la nielle. Mémoires de Mathématique et de Physique,
Présentés a L'Académie Royale des Sciences, par divers
Savans, et lûs dans ses Assemblées. Tome Troisième. pp.
68-85.
by Janis Antonovics
In later literature, I have found that Aimen is usually written as Aymen.
These are words that I sometimes translate, at other times I don't!
charbon = blight
nielle = smut (actually in the first part this is loose smut of barley - Ustilago hordeii)
pieds = plants (individuals)
vice =affliction,
malade = diseased
mal = disease
sommets = anthers
filets = filaments
support = receptacle, rachis node
Page numbers in square brackets refer to pages in the original
[p.68]
Memoirs Presented to the Academy
Research on the progress and cause of floral blight
By M. Aimen Correspondent of the Academy
Plants offer us phenomena that resemble those seen in animals: they live,
grow, multiply, at least certain organs, each destined to particular functions.
Plants are indeed subject to disorders, often their organs are disturbed and
damaged in their action, the fluids being carried there in greater or lesser
quantity; in fact plants can become ill. This state contrary to nature has
above all been observed where it has been the most striking: agriculturalists
notice it very often in trees and herbs which are useful to us. The curious
have as a consequence made the same observations for some other vegetable
species; but these observations, if one can call them such, have been
constantly restricted to examining particular defects of plants. I don’t know
of any author who has pushed the researchers further; and in all of the works
that I have read, I have found very few exact descriptions of these kinds of
illnesses. What has surprised me the most is that I have never seen anything
clear and true in everything that has been left to us on the illnesses to which
cereals are so subject; this subject has been treated however by men most
distinguished in agriculture, in natural history, and by physicians of the first
rank. Without doubt satisfied to know the effects of the malady, they have
scarcely applied themselves to observe the different states, the progress and
the causes. This is what several researches that I have had the opportunity to
carry out in the vicinity of Paris and in the Guienne [SW France] have
[p. 69]
convinced me; it is these researches that I propose to present to the Academy
of Sciences. I will today detail the discoveries that I have made on the smut,
and I will try to describe this malady more clearly than has been done, and
with all the accuracy that a large number of observations often repeated,
with the most scrupulous attention, always produce. I will examine if some
similar malady is found in other herbs, and I will compare them together. I
will only write on what I have seen, and which all the world can see, because
I believe that in physical researches it is worth more to listen to the facts
than to reasonings.
None of the authors that I know have exactly determined what this
“nielle” might be. Some have believed that this might be an illness little
different from smut or ergot; some have described smut or ergot under the
name of “nielle”; while finally others have grouped the three diseases
together. For us, we understand “nielle” to be the defect that reduces the
flowers of cereals to a black powder.
Before getting to know this illness, it is appropriate, I think, to
examine the spike of cereals in its natural state, after which one can compare
it with a diseased spike; and as the parts which make up the spike of
different cereals are in many respects the same, I will only give a description
of a species that is rather common throughout, namely barley. I have chosen
this small cereal because it is this out of all of them that is most often
smutted.
The spike of barley is an assemblage of several clusters of flowers
arranged, opposite and one above the other around a common axis, which is
called the rachis of the spike. Each cluster of flowers is attached at a tooth of
the rachis, that is to say, at a small protrusion of the common axis; this small
protrusion is the support [rachis node] for the flower. The support has a
small circle of white hairs on each of its two sides, and at the posterior a
small depression in line and half the height.
Each cluster has three flowers, and each flower has two calices, the
[p. 70]
common or exterior calyx which has been called the husk, and the proper
calyx of the flower which some botanists consider to be the petals [Side
note a: Linnaeus, gen. Plant. gen. 80; & inde. Van Royen flor. Lugd. pag.
52.]
The exterior calyx is composed of two raised membranous parts,
somewhat concave, wide in a line at the place of their insertion, and which
ends in a point.
The calyx of the flower is also made of two membranous parts, wider
and longer than those of the exterior envelope. The exterior piece, which is
the largest, is concave and ends in a long awn with small teeth; we French
call it the beard of the spike. The interior piece is flat, less wide and less
long, but of a whiter and finer tissue than the former; it also terminates in a
point.
None of the parts I have talked about deserve the name of petals; the
only organs to which one could give this name are two small white
membranes, thin, transparent, rounded at the tip, wider in the superior part
than in the inferior, arranged at the base of the flower around the embryo,
resembling quite the wings of a fly. [Side note b: Micheli gen. plant. pag.
35.] ; small hairs edge these petals, which Malphigi first saw in the cereal
from Turkey. [Side note c: Anat. plant. pag. 52, tab. 35, n. 215.]
The calyces enclose the stamens and the pistil. The stamens number
three; they are in two parts, the filament and the anther. The filament is a
kind of white stalk, straight, thin, hair-like, to which the anther is attached;
the anthers have an oblong and quadrangular shape, each of them is
composed of two capsules back to back one against the other, and made of
an elastic membrane which contains a powder that it releases after a certain
time. One says that the stamens are the male organs of the flowers.
The pistil occupies the center of the flower; it is made of three
different but continuous organs, and which, although they only form one
body, are distinguishable into an embryo, styles and stigmas. The embryo is
only the first rudiments of femaleness; it is conical in shape; the styles are
[p. 71]
two small filaments divided at the embryo; these filaments are whitish,
round, short, hairy and support the two stigmas, which are two white bodies,
bordered with hairs, or papillae filled with a liquid; these three organs form
the female parts of the flower.
The flowers in which the stamens and the pistil are found are
hermaphrodites; those in which there are only stamens are male flowers;
these two sorts of flowers are found in a species of barley and in several
other gramineae; the first have a constant femaleness, the second are always
sterile.
The most remarkable parts which we have just described are the
stamens and the pistil; it is these that carry out the fertilization and the
multiplication of the plants. I don’t agree with that; it has been shown today
that fertilization in plants occurs in the same manner as it is carried out in
animals. One is convinced that the stamens are the male parts, and the pistils
are the female organs of the plant; one is aware that the dust which the
anthers release is the flour of fecundation.
These then are the parts that make up the spike of barley; now let us
examine what changes the “nielle” produces and what is the organ that is the
first to be attacked. The detail of my observations is, I think, the best way to
give an exact knowledge of it; I will thus report here what I have observed
during the years 1751, 1752 and 1753.
The cereals had hardly started to form spikes when I went in the field:
I pulled up several stems of barley; I opened the sheath, which is made of
leaves in order to see if the spike was corrupted before being exposed to air.
I confess that in my initial tries, I damaged a lot of healthy spikes; this only
added to the appreciation of the force with which I experienced when I
suddenly came to distinguish the healthy spike from the unhealthy spike.
And here are the symptoms: 1st the sheath of the healthy spikes is larger,
more swollen, above all in its middle: 2nd the attacked spikes have an odor
[p. 72]
comparable to smoked herring [Side note a: Rudolph. Jac. Camerarius,
dissert. de ustilagine pag. 3.]: 3rd when the ill spikes start to begin to expand
the sheath, their awns, which are the first to emerge, make them
recognizable from a distance; for it is white, in contrast the awns of the
healthy spike are green. The first time that I saw this symptom, I already
knew that it was known to the famous Mr. Wolf [ Side note b: Entdeckung
der waren Ursache, &c. cap. 4. s. 16.]
I then carefully examined the ill individuals before the spikes opened.
The roots, the leaves, the stem always appeared healthy to me,
When I had opened the sheath of the spikes that were less developed, I
noticed that the upper flowers were yellowish; those lower down has small
spots, and the inferior ones were white. Three days later, having examined
new spikes, I saw that the inferior flowers were spotted and started to
become yellowish; then the color of the superior flowers turned to black, and
they became entirely this color twenty four hours later, even if the spikes
had been separated from their roots.
Having made these general observations, I examined each part of the
spike in particular, and I saw that the husks were more pale, more narrow,
more short than the natural state; that the awns scarcely had a twelfth of the
length and size that they were in a healthy spike, and that they were curved
in various directions.
When one and the other of the calyces had been removed from the
husks, the petals were scarcely visible, they were so little: the filaments were
twice as short and thin than in the natural state; the anthers did not contain
any dust; their capsules were empty, white and withered.
The stigmas were equally small and thin; one could not notice the
papillae, even with a lens. The embryo appeared smaller and more round:
the support of the embryo was larger and more swollen; one noticed there a
small black spot. As I wanted to observe the progress of this illness at every
time interval, I took a dozen spikes in which the flowers were in the
described state, I put them in a jar containing water; this enabled me to see
[p. 73]
that the black spot of the support became larger hour by hour. The number
of black spots soon increased; the tumor of the support also increased in
proportion; to me it appeared, twelve hours after the first examination, to
make a glandular body or a particular parenchyma. Finally, a little after the
support of the flower was in this state, the black spots opened and out of
there came a thick substance that clotted into small, round and balck bodies,
depending on the evaporation of the humidity.
The ulcer and the tumor spread: the stamens were, after the support,
the parts of the flower that were harmed the first. We said that they were
initially very small; but scarcely had the malady started to attack them that
their basal region became extruded, swollen, and unequal; the ailment
multiplies, it soon occupies a part of the filament , but never enters the upper
part. If when this organ is in this state, one examines with a good lens of
four to five lines of focus, one notices small black dots which penetrate the
interior. These spots examined two days later, no longer seem to be the
same; they are bigger and allow the production a substance in all respects
resembling those which one has seen leaving the support. The progress of
the black spots or ulcers are then so rapid that if one allows two days to pass
before examining them, one finds that the filaments are totally consumed;
one only sees in their place very thin filaments, covered with dust into which
the material that comes from the ulcers has changed.
From the filaments the illness passes successively to the embryo and
to the styles; it produces the same phenomenon in these parts but one
scarcely notices the progress that it makes there. One neither knows what
progress the “nielle” makes in the petals, in the stigmas and in the anthers, in
that these organs are reduced.
Soon after one has noticed this illness in the filaments, one sees it in
the calices: some black spots situated at the inferior extremity of the awns
make it distinguishable; these spots are penetrating.
[Footnote: Sav. Etrang. Tome III ]
[p. 74]
The disease having reached this state, it is no longer possible to
distinguish anything else other than that the husks, very thin, black, pierced
in several places, still resist the swelling of the materials that they enclose:
this swelling increases from moment to moment, then the ulcers produced in
this liquid that I have spoken of, thus the quantity of dust becomes much
greater. Then, if after having lifted up with the point of a needle the husks
that are very easy to rip apart, one examines the substance of the tumor, one
finds suddenly that it is covered by a very thin skin, that it is only made of
some solid fibers, of divers organs, and of a quantity of black dust; and like
these dusts, on drying, they are attached to the surface of the solid filaments,
they are together a spongy mass that persists in the same state till the spike
finds itself exposed to the sun, the husks are torn into small clumps, and
allow the dust to escape, which, drying to their advantage, are separated
from the solid filaments and become more black and more fine; finally, at
times by rain and at times by wind, the solid fibers and the black dust are all
removed, the rachis of the spike becomes naked. These are the diverse
symptoms and the different degrees of the illness named ustilago [italics in
the original] by the ancients, in a word, the true “nielle” of cereals.
All the smutted spikes however are not totally destroyed; I have seen
it two or three times where the inferior flowers were reduced to powder, but
where most of the superior flowers appeared at first sight to be in very good
condition: in effect, the calices and awns of these flowers were not attacked
by the malady, only the organs of reproduction are destroyed; which no
doubt only results from a smaller degree of the illness.
From the floral organs the “nielle” does not pass to the stem nor to the
leaves, not even to the rachis of the spike; all of these parts usually remain
healthy; sometimes one sees black spots on the stubble, but these spots are
of the same type as those that oen sees on the straw of healthy spikes; thus
[p. 75]
the “nielle” is not a malady of all the parts of the plant, but only a malady of
the various organs of the flower.
The symptoms that I have just described in the smutted barley are the
same in the other cereals attacked by this illness.
Oats, wheat, spelt are subject to being smutted, less in truth than
barley: rye also get it, although more rarely. I have seen several species of
couch grass attacked by this malady, among others that which was named by
botanists, gramen dactylon angustifolium spicis villosis. C. B. p. 8. [italics in
original].
Among the species of barley, the six-rowed winter barley
[l’escourgeon] is the most subject to smut. I cannot finish without having
remarked that an observer can see at the same time, and in the same spike,
the different states of the illness: if e examines the lowest flowers he will
find the illness at its beginning, and he will see its progression as he carries
his attention to the upper flowers.
The various degrees of alteration that we have just described in the
smut of cereals, are they particular to the grasses and does one not find them
in other plants? This is what most of the authors have neglected to examine,
or have examined it little; but it is not something that a careful observer can
pass in silence in a subject where he deals with maladies in that precise
knowledge can bring about much utility; thus I do not believe that I can be
accused of leaving my subject, if I examine, in passing, some herbs in which
I have observed the smut; I am even forced to report that which I have seen,
because some authors have remarked that certain plants are subject to have
their flowers reduced to powder. J. Bauhin, Ray and some others have seen
this illness in a species of black salsify [“scorsonère” - Asteraceae] [Side
note a: Scorzonera palustris pulveriflora. H. R.], and in a species of lychnis
[Side note b: Lychnis sylvestris alba simplex. C. B. p. 204.], Mentzel in
persicary, Morison in the goatsbeard [“la barbe de bouc”]. In reading these
observations, I suspect hat the flowers of these plants can only be reduced to
powder by a disease somewhat different from the “nielle”: my supposition
seems reasonable. I will describe the malady that I have seen in the male
flowers of the species already named lychnis [original in italics]. The
[p. 76]
curious will easily forgive me this digression, that the malady of lychnis is
the same as that of the cereals, and that this plant, which is so common in
our countryside flowers from the first days of may right till the end of
October, furnishes all the conveniences for good observation: in addition the
flower of this plant being a certain volume, they show to the eye that which
one can only see in the cereals with a lens.
The diseased flowers of this lychnis are never open completely; their
various parts are smaller than those of healthy flowers; scarcely do the first
start to be smutted when the base of their calyx becomes larger and rounder,
the sides increase in proportion, and the external surface becomes unequal;
this inequality becomes more considerable, to the degree that the calyx
swells even more, that is to say, to the degree that the illness progresses. The
smut of lychnis has its basis in the support of the flower: it forms in this part
a glandulous substance which is marked in several places by small brown
raised spots. These spots rapidly become true ulcers, from where there flows
a thick liquid which changes, while drying, into purple dust. The filaments
of the stamens are then attacked, they become fleshy; their external surface
hardly changes color, while they are filled on the interior by a green
parenchyma; the base is the first part of the filament that becomes ulcerated.
The ulcer becomes larger, and then takes over part of this organ; for the
upper part of the filaments nor the anthers have never appeared tot me to
increase in size. From the filaments the “nielle” moves to the petals, their
middle part becoming blistered, the epidermis becomes raised, and allows
one to discover an ulcer in which the edges are callous: it happens so much
to the part inside the calyx, that all parts of the flower are reached by the
ulcers which produce dust similar to that which come from the axis
{“support”]: finally, like in the cereals, the ulcers invade these parts
completely and one only sees it in
[p. 77]
the interior of the calyx as a mass composed of purplish dust and some solid
fibres. The female flowers of this plant are also subject to becoming
“nielled” * [* footnote: Mr. Linnaeus had reported in his Hort. Cliff. 170, an
observation on this plant, in which he he had seen females all covered with the
fecundating dust. I positively believe that this great botanist had seen flowers attacked by
the “nielle”; he had indeed seen them covered with a purplish dust, but this dust is not
that which fecundates the plant germs]; all the flowers of one stem are always
afflicted. This is the observation that I did not wan tot pass over in silence,
because it is certain that strange facts, but of the same kind, shed light, and
perhaps a little weight, to newly found truths.
The “nielle”, which in cereals and lychnis has its principle in the
support, and which in this latter plant affects the filaments that are attached
to the anthers, present a different phenomenon in the male flowers of maize,
or Turkish wheat [spelt?]. In this plant, this affliction has its principle in the
anthers; there it is its seat, and it doesn’t appear to change the filaments: the
petals nor the different parts of the calyx are scarcely afflicted. The
quadrangular anthers, on the contrary, which they are in nature, become
thick, inflates, rounded in shape, and crossed from one extremity to another
by four small furrows which become smaller in proportion to the degree that
the anthers enlarge, and which eventually disappear. At first these anthers
are a dark yellow, a little later one notices with a lens some small black spots
which spread as the disease progresses; finally the locules separate from
each other and allow the dust, which is sometimes brown and sometimes
black, to escape.
All the flowers of a panicle in maize are “niellees”; but it is interesting
to observe that even if the male organs are totally lost, the female spikes,
which are separated from them are in no way afflicted; they carry healthy
grains which are probably fecundated by the stamens of neighboring
[78]
individuals; new proof that is quite convincing that “nielle” is not a general
affliction of all the parts of a plant.
The flowers of the wild carnation a [a side note: Caryophyllus sylvestris
vulgaris latifolius. C. B. p. 209] are subject to the same species of “nielle”: the
anthers are the only part of the plant which are attacked by it; in this state,
they have a purple color. Mr. Bernard du Jussieu observed the disease of
this plant first in 1751; he had the kindness to tell me the same day. We
observed on a large number of individuals of this plant that all the flowers of
one individual were afflicted. Since then, I have seen and carefully
examined this carnation in several provinces, among which all the flowers
were smutted in the same fashion. I have seen the same disease for two
species of morgeline b [b side note: Alsine altissima nemorum. C. B. p. 250. Alsine
pratensis gramineo folio angustiore Inst. R. H.], on savoniere [soapwort] c [ c side
note: Lychnis sylvestris quae saponaria vulgo. Inst. R. H.], on a muscari d [d side note:
Muscari arvense latifolium purpurascens. Inst. R. H.]; Mr. Bernard de Jussieu
observed it on a species of berce e [e side note: Sphondylium vulgare hirsutum. C.
B.]; and Mr. Buttner, a Prussian botany scholar, told me that it in the area
around Gottingen he had found, with the famous Mr. Haller, flowers of
phellandrium attacked by this affliction.
I believe that one cannot distinguish these species of smut by the parts
that they first attack; thus this disease could be named in cereals the mut of
the axis, and in maize and carnation the smut of the anthers.
I have seen it in statice, commonly known as the seven-stemmed herb,
an affliction which begins in the anthers; but this affliction is completely
different from the smut.
I will not report here what I have seen in the smut of salsify
[scorsonere]; I will only say that that this disease doesn’t appear to be the
same as that of the cereals, and it merits a separate dissertation.
It is surprising that so many enlightened naturalists have not
recognized the stages of the disease which we have just described; stages
which are so simple, so visible, and which cost so little to observe, which it
seems that they should have been known for a long time; nevetherless no
one that I know has described them. I admit that the symptoms of this
affliction may have escaped from my research, if Mr. Bernard de Jussieu, of
the Academy of Sciences, had not taken the trouble to review the
[p. 79]
observations that I had already made, and make new ones with me.
The causes of smut have not been better known than its stages: some
authors have copied each other, and most of tehm have neglected to examine
this affliction before the spike had emerged from its sheaths; others had been
attentive, these are Tragus, Tabernae-montanus, J. Bauhin, Ray, Camerarius,
Mr. Wolf, and some others. The former have said almost nothing; only Mr.
Wolf had seen with a microscope the small balck spots and invasion of the
awns of the spike a [ a side note: Entdeckung der waren Ursache, &c. Ch. 4. p. 18.].
he believed that the smutted tumor was nothing other than the division of the
embryo into three parts, from which he conjectured that the cause of the
smut was a monstrous condition of the embryo; for according to him, the
smutted grain is a monstrosity made up of three bodies b [b side note: Loc. Cit.
p. 17.]. The respect that I have for this scholarly man has to cede to the truth;
I cannot but say that he is mistaken on this point; he has indeed seen three
smutted bodies for each support; but, we have already noted that each
support carries three flowers; moreover, the cause of the smut in no way in
the monstrous state of the embryo, because it is the flowers that are smutted,
and which however don’t have one [an embryo]; these are, for the most part
the flowers of winter barley: in effect this species of barley has only one
hermaphrodite flower in the middle of two male flowers, and all three are
nevertheless equally smutted.
Theophrastus c [ c side note: Hist. Plant. bk. XVIII, ch. VII, p. 342.] , Pliny d
[ d side note: Hist. Plant. bk. XVIII, ch. XXVIII, p. 476.], and their followers
[copiers?] believed that the cuse of smut was abundant rains, or that that
which the agriculturalists' named ros mellitus. How could that be possible,
because the spike is smutted in the sheath, a sheath that is completely closed
so that it is impossible for rain or any other liquid to penetrate in there? This
same reason proves that those who have thought that this affliction comes
from the sun, are equally mistaken: if the sun burned the spike that is still
contained in the sheath, would it not burn, or at least would it not alter the
leaves of the sheath?
The smut is certainly not caused by small worms, because one sees no
[p. 80]
opening, no passage whereby they would have been able to enter; moreover,
they are not seen with a microscope, when, using this methods the first
ulcerated spots are detected, which are no larger than the point of a needle.
Without doubt the authors of this opinion have observed, like us, that in
certain smutted spikes there are small worms which feed on the black dust;
but if they had paid more attention, they would have noticed that these
worms are only found on a small fraction of the diseased spikes, and only
when the smut is in its last stages; they would have also noticed that these
same worms are also found on healthy spikes.
Wepfer saw some very small red worms on the roots of smutted
cereals a [ a side note: Miscel. nat. cur. dec. X, pag. 324.] where he thought
they were the cause of the smut. All other physicians will no doubt not
believe this to be the case; it is really often that one sees and that one cuts
down trees in which one has not seen the least sign of any affliction in the
flowers, although not only the roots but also the trunk is invaded by insects:
it is also known that if insects feed on a tree, by destroying the roots, the
flowers and the fruits are not attacked more particularly by some affliction
than are the leaves, trunk, etc. Every day our gardeners cut a certain amount
of the roots of the plants that they transplant; these plants grow better than if
one did not cut any roots. Besides, I have seen, just like Wepfer, the small
red insects in the roots of cereals; but I have seen them attached indifferently
to the roots of healthy cereals and smutted cereals: however they are not
found everywhere, being found only in dry places, in which the piles of soil
have not been well flattened. I have found two species of insects on the roots
of cereals, one being a mite b [ b side note: Acarus terrestris abdomine depresso.
Linn. Faun. Suec. 1200] and the other a flea * [* footnote: this insect not having been
named, I will call aphis graminum.].
Some physicians are surprised that the smut could indeed come from
the p of some insect; without doubt because they have not paid attention,
[p. 81]
1st, that these insects are found equally on healthy spikes as on smutted
spikes; 2nd, that these insects do not have an own organ suitable for biting.
Everyday in the pods of legumes we find seeds which serve to house insects
without them being attacked by this malady. A fly pricks the fruits of the
cherry, the plum, etc. without one finding any other affliction other than the
presence of the insect. Mr. de Reaumur found same small caterpillars in the
grains of barley that were not smutted * [* side note: Histoire des Insectes, vol. II.
Memoir 12.] . Anyway, how could this insect exactly prick all the flowers of a
spike which is already well enclosed in an envelope? How can it attack all
the spikes of one individual? Why does it never attack some particular
flower? Why are the organs of the smutted flowers ten or twelve times
smaller than they are in their natural state? that which is the opposite of the
effects of pricks by insects.
I have very often found a fly which pricks the young fruits of madder,
even depositing its eggs there; but I have never seen that this puncture
produces something that resembles smut, I have only seen that it sometimes
results in the sterility of the fruit.
One cannot say that this disease derives its principle from an affliction
of the sap: the state of the straw and the leaves proves quite the contrary.
The sap furnishes the proper juice to nourish the different parts of the
cereals; given that this juice is afflicted, why are only the spikes affected by
it? Why are the other parts of the plant not affected at all?
We will not stop any longer to destroy hypothetical ideas: it is time
[p. 82]
that we gave the true cause of smut, that which is presented to us after much
research.
In the description of this disease I said that its cause was a state
against nature in the support, a local affliction of this part, which results first
of all in a tumor and then an malignant ulcer which invades all the parts
involved in fertilization. It still remains for us to examine the more distant
causes, that is to say, the causes that produce the tumor.
Ray a [a side note: Hist. Plant. book XXII, ch. II.], Florinus b [b side
note: Oecon. Prud. Book III, ch. XIII, p. 5.] and Becher c [c side note: Ibid. p. 31.]
conjectured that the smut came from an affliction of the seed; this idea
seemed probable, I worked to verify it. To do this, I took a handful of the
same species of barley, and I examined all the grains of it one after the other,
I there found several variations; some were fatter, and gave way to the
pressure that others of the same size presented; some were of an ordinary
size and also resisted under the fingers, when a quarter of the same volume
gave way; some were of a darker color: others had a covering cracked in
several places, or withered, wrinkled and devoid of flour. And several others
had the two extremities in the same condition; some seeds were the shortest,
the lightest and the softest; others were marked with small spots situated in
various ways, these spots were covered with mould; some of these seeds,
finally, served as lodging for small caterpillars of moths, or of weevils. I
separated these very different shaped grains, I put each in papers which I
numbered with care, I sowed all of them separately in places that I marked,
but in the same piece of ground.
The largest proportion of my grains emerged: there were some that
did not come up; these were those that had their two extremities affected,
and those which elongated, and the thinnest and the hardest. Most of the
seeds that I recognized served as lodgings for caterpillars, came up, but
some did not grow, because no doubt these insects had introduced germs.
The seeds of this kind that came up, did not produce individuals as
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vigorous as the others, but also their spikes were not in the least smutted.
All the molded grains that came up, had smutted spikes; thus I had to
conclude right away that the mould of the seeds was the primary cause of the
smut, if among the other seeds that I had sown none could be found which
carried smutted spikes. I first of all suspected an affliction in the seeds that
produced the same effects as mould; but what is a suspicion in reality [en
physique]. I have examined with the lens all the kinds of grains that I have
separated all with each other, and I have noticed nothing: moreover, in the
sites where I had put seeds that were very similar, I found healthy and
nielled grains. I therefore believe that the mould can attack the grains, no
matter what covers the soil, and all the more so as mould is produced most
often by humidity. I wanted to verify this idea; to do this, I chose several
grains of barley which did not show any trace of external disease and which
appeared to be of the same consistency to touch. I sowed them, they
emerged on the seventh day; I harvested them and examined them each
separately. The seeds, for the most part, did not appear to have any damage:
I found eight to nine of them which had their outside covered in several
places with white small threads: this was a species of mold. I carefully put
the remaining grains back in the soil, and they produced nothing but nielled
spikes; I have repeated this experiment for three years, and with the same
success, Here is a well-known cause of nielle: there could be others that my
observations have not yet encountered.
The mold of the grains is thus one of the causes of the nielle: how can
it produce this disease, other than by changing the internal disposition of the
seed! And it is this that makes all the flowers of the same spike, and all the
spikes on the same individual consistently nielled. One might object perhaps
in a work on the multiplication of the
[p.84]
grains, Mr. Wolf says he has observed an individual of oats which produced
a bunch of spikes in which some were healthy and the others nielled* [* Loc
cit. p[para.?]. 18] I believe that on this occasion Mr. Wolf has mistaken the
blight [charbon] for the nielle: however, if Mr. Wolf has spoken of the true
nielle, I think, and I dare to suggest that in this case the bunch of spikes had
been formed from at least two individuals, that is to say, an individual
healthy and one individual nielled; something that has happened to me
sometimes. I have often seen two or several individuals of corn which had
their roots so interlaced that one could mistake them for one individual, and
so see there, healthy spikes and nielled spikes; that is why it is necessary to
dig them up and separate one from the other to see properly
But why does this cause not infect other parts of the cereals? A
general disease of the parts of the flower is well known; that which makes
the flowers to be the only part that is attacked will perhaps never be known:
it appears to depend on the structure of the organs whcih is impossible to
determine. One can only, from observations of this disease, infer that there
are in plants certain diseases affecting some parts and in which the cause
comes from the seeds and continues to have an effect during the
development or production of the same parts. An observation which tends to
prove this is that I have seen individuals of the wild carnation produce
nothing but diseased flowers over a period of three years. One can only say
that this affliction, which comes from the seed, perpetuates itself in the
production of the anthers and the pistils of all the flowers? It is perhaps a
depraved seecretion, from which results in an ill-formed spermatic liqueur ,
deprived of its active principles and totally altered with regard to the
quantity, the form and the shape of the globules or grains resembling dust
which must result from it, as soon as the humidity held there is released.
How this is formed, how is the tumor of the support ulcerated? I
admit that below I can only give conjectures: the movement of the sap juices
can hardly be seen; the vessels in these parts are so small that it is
[p. 85]
impossible to carry our successful research on this material. I will hazard, I
repeat, a conjecture which to me seems probable.
The support in the grasses, as most botanists have observed, produces
a sweet, honeyed fluid of which a proportion of which seeps around the
embryo, and of which the largest part serves as nutrient for the parts of the
flower: when this fluid cannot get up to the organs of the flower, it must stay
in the receptacle, so disturbing the organization, so distending the vessels,
and as a consequence making this part larger than usual. The sap will stay
there and stagnate there; it will then become corrupted, as do all fluids which
stagnate, and above all the fluids which, like this one, easily turn sour.
I have said that this conjecture is likely because the stem of the cereals
being in its natural state, the vessels of this part transmit the same quantity of
sap-like juice. But this same quantity of sap will not pass into the various
parts of the flower, because they are much smaller than in their natural state.
I will give in a second memoir the details of the causes of ergot and
blight [charbon], and the means of preventing these diseases. I will report
particular observations on the blight of corn, and on the cuases of sterility in
the spikes of cereals.