1842.] Linnean Society. IGl 



This paper contains the results of experiments made by the author 

 with the view of determining the mode in wliich the sporidia of the 

 fungus which he regards as the cause of Ergot are introduced into 

 the infected grass. 



In March 1840 twelve healthy grains of rye, of wheat and of bar- 

 ley were placed in a shallow glass vessel containing a sufficient 

 quantity of distilled water to moisten them, and covered with a glass 

 shade. When germination commenced an ergot of wheat of the pre- 

 ceding year was immersed in the water, the sporidia on its surface 

 were detached, and the ergot itself was then removed. The same 

 experiment was performed with sporidia obtained from an ergot 

 of Elymus sabulosus. Sevex'al days afterwards, when the leaves had 

 attained a length of three or four inches, the young plants were 

 conveyed into the country and planted side by side in a garden. At 

 the period of harshest there remained alive only four plants of the rj^e 

 (one of which had been infected from the ergot of Elymus, and the 

 remaining three from that of wheat), three of the barley and four of 

 the wheat. Of the rye scarcely a single ear produced healthy grains, 

 the paleae being generally quite emptj' ; but nine of the ears contained 

 ergots, some furnishing only a single specimen, and others as many 

 as six. The ears of the barley were filled with healthj^ grains, and 

 only one apparently diseased grain was detected ; while in the wheat 

 the ears were full and without disease. 



As in these experiments no grains from the same sample were 

 sown which had not been subjected to the influence of the sporidia 

 of the fungus, Mr. Quekett made in the following autumn another 

 experiment with the %iew of supplying this deficiency. Twelve 

 grains of rye, of wheat and of barley were again made to germinate 

 under similar circumstances to the last, and the sporidia obtained 

 from the surface of one of the ergots of rye produced in the first ex- 

 periment were diffused in the water in which they grew. These were 

 planted in October on the same estate, but not within half a mile of 

 the former spot ; and twelve healthy grains of each kind which had 

 been carefully kept apart from the others were planted in the same 

 locality. Very few of the plants arrived at maturity, and in August 

 last there remained of the infected plants only two of rye, two of 

 wheat, and one of barley ; and of the uninfected plants one of each 

 kind. On each of the plants of rye which had been subjected to the 

 influence of the sporidia an ergot was discovered, and the ears as be- 

 fore were almost entirely devoid of healthy grains ; while the plants 

 of wheat and barley subjected to the same influence produced perfect 

 ears and healthy grains. The three plants of rye, wheat and barley 



No. XVII. — Proceedings of the Linxean Society. 



