208 



RESEARCHES ON FUNGI 



« 



environmental conditions. This view 

 was held up to about the middle of the 

 eighteenth century ; but, by that time, 

 it had already been suggested that the 

 cause of the disease might be of external 

 origin. 



With the discovery of the infective 

 nature of bunt by the Abbe Tillet x in 

 1755, a new field of experimentation, 

 which might serve as a step toward a 

 clearer conception of the causal factor, 

 was opened up. In adjacent rows in 

 a field, Tillet sowed (1) wheat grains 

 artificially dusted over with bunt spores 

 and (2) clean wheat grains free from 

 spores, ahd he found that the wheat 

 plants derived from the dusted grains 

 developed bunted heads, whereas those 

 derived from the clean grains remained 

 perfectly healthy. These experiments 

 were soon repeated by other workers 

 and, in the main, with confirmatory 

 results. 



In 1807, Benedict Prevost, 2 with a 

 scientific outlook far in advance of his 

 time, succeeded in germinating the 

 minute black bodies obtained from the 



Fig. 100. — An ear of wheat in which the 

 mycelium of Tilletia tritici has invaded all 

 the spikelets and has produced chlamydo- 

 spores in every grain. The grains have thus 

 been converted into smut-balls, ss. Drawing 

 prepared by photographing, re-shading, and 

 slightly modifying part of a coloured wall- 

 diagram issued by H. Tuboeuf. Slightly 

 larger than natural size. 



1 H. M. Woolman and H. B. Humphrey, Summary of Literature on Bunt or 

 Stinking Smut of Wheat, U.S. Department of Agriculture, Bull. No. 1210, 1924, p. 4. 



2 B. Prevost, Mhnoire sur la Cause Immediate de la Carie ou Charbon des Bles, et de 

 Plusieurs Autres Maladies des Plantes, et sur les Preservatifs de la Carie, Paris, 1807. 



