190 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 



repeated occasions without being treated to beer mash. An incident 

 connected with these experiments which we made is, however, well 

 worthj^ of being mentioned j because it shows how very easily single 

 experiments may lead to false hopes and conclusions. A certain pro- 

 portion of the last-named larvae — the proportion differing in the differ- 

 ent lots treated — perished before or while transforming to the chrysalis 

 state. They became flaccid and discolored, and after death were little 

 more than a bag of black putrescent liquid. We should have at once 

 concluded that the yeast remedy was a success had we not experienced 

 the very same kind of mortality in previous rearing of this larva, and 

 had we not, upon returning to the field from which the larvae in ques- 

 tion were obtained, found a large proportion similarly dying there. 



Though from this experience we had little faith in the value of the 

 proposed remedy as against the Cotton Worm, we nevertheless took 

 pains to have it tested in 1879 both by Professor Smith in Alabama 

 and Professor Willet in Georgia, and in 1880 by Messrs. Bailey, Hub- 

 bard, Jones, Schwarz, and Stelle in various parts of the cotton belt. 

 The experiments were made in each instance during the latter^part of 

 the season, when the vitality of the worms was already considerably 

 lowered, a condition which, in our experience with fungus diseases in 

 insects, was eminently favorable for satisfactory trial. But in spite of 

 these favorable conditions the uniform result of all the experiments 

 showed that there was no insecticide virtue in the ferment. For this 

 reason we merely add it to the other substances just enumerated which 

 proved to have no insecticide property. 



