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XXIX. On the Ergot of Rye. By Francis Bauer, Esq., F.R.S. & L.S. 
Read January 21st, 1840. 
THE existence of this most remarkable disease in gramineous plants, parti- 
cularly in Rye, has been known from time immemorial. Many authors, both 
ancient and modern, have written much on the subject of Ergot, but they 
considered it with reference only to the injurious effects which it has on the 
animal health. 
The Abbé Tessier in his Traité des Maladies des Grains, published at Paris 
in 1783, gives an account of many important, and, generally speaking, very 
satisfactory experiments, as well by chemical analysis of the substance of the 
ergot of rye, as of the pernicious effects it has both on the human species and 
on brutes; but the opinions held on its nature and origin are to this day very 
unsatisfactory. 
After more than twenty-five years’ attentive observation, I am convinced 
that these opinions and conjectures are totally erroneous and without foun- 
dation. 
The difficulty of tracing the origin of this disease undoubtedly arises from 
the fact, that not the slightest indication of its existence is observable either 
in the infected ear or in the plant till the ergot actually emerges from the 
husk in which it is formed, when it is too late to determine its origin. 
It was about the middle of August 1805 that this disease came first under 
my observation, but then the rye was nearly ripe and the ergots full grown ; 
consequently I could form no judgment: and it was not till the middle of 
June 1809 that I was enabled to prosecute and complete my investigation, at 
least so far as to ascertain what the ergot really is. 
The rye was then just in blossom, but there being no external appearance of 
