THE CANADIAN ENTOMOLOGIST. Ill 



odicals, and the final result of my study of those reports was the conviction 

 that a remedy for insect pests, offering several prominent advantages, 

 could be found in the easy application of the yeast fungus. Further, that 

 this remedy could be used probably against the famous Colorado grass- 

 hopper, for the destruction of which the Government has appointed a 

 commission appropriated with $75,000 ; also, that the remedy could be 

 tried in an easy way against the obnoxious hairy caterpillars, against the 

 potato bugs, and last, but not least, in every greenhouse against leaf lice 

 and similar pests. 



Dr. Bail asserts that he has proved by many skillful experiments that 

 four species of microscopical fungi are merely different developments of 

 the same species. One of them, the fungus of the common house-fly, is 

 the vexation of every housekeeper. The dead flies stick in the fall firmly 

 to the windows, or anywhere else, and are covered by a white mould not 

 easy to be removed. The second is the common mould, known to every- 

 body and easily to be produced on vegetable matter in a damp place. The 

 third is the yeast fungus, a microscopical species and the basis of the work 

 done by yeast of fermentation. The fourth is a small water plant, known 

 only to professional botanists. Dr. Bail contends that the spores of the 

 fungus of the house-fly develop in water in this last species, out of water 

 in mould, and that the seeds of mould are transformed in the mash tub 

 into yeast fungus. 



The experiments made by Dr. Bail cover a period of more than a dozen 

 years, since the numerous objections which were made against his results 

 induced him to repeat again and again his experiments in different ways. 

 I am obliged to state that even now prominent botanists do not accept 

 Dr. Bail's views, which he maintains to be true and to be corroborated by 

 new and sure experiments. This question, important as it may be for 

 botanists, is without any influence regarding my proposition, as Dr. Bail 

 has proved that mould sowed on mash produces fermentation and the 

 formation of a yeast-fungus, which kills insects as well as the fungus of the 

 house-fly. I was present at the lectures of Dr. Bail before the association 

 of naturalists, in 1861, which were illustrated by the exhibition of mould 

 grown on mash, on which the fungus of the house-fly had been sown, and 

 by a keg of beer brewed from such mash, and by a cake baked with this 

 yeast. Both productions were declared perfect by all who tasted them — 

 an experiment in which I did not feel obliged myself to join, as both are 

 to be had prepared without the fungus of the house-fly. 



