REPORT OF THE ENTOMOLOGIST. 319 



animals. Tlie neglect to expeiiiuejlt with tliis powder upon the cottou- 

 worms thid .seasou is not a serious matter, as it is not yet produced in 

 this country in sufficient quantities to admit of its taking the place of 

 remedies we now have. We understand that arrangements have been 

 made for growing the i)lants upon a large scale, and before the substance 

 can be put upon the market in large quantities the necessary experi- 

 ments to determine its efficiency and the best mode of application will 

 have been made.* 



Yeast. — In the Canadian Entomologist for June, 1879, Dr. H. Hagen, 

 of Harvard University, published an article on the destruction of obnox- 

 ious insects by the use of fungi. The article was based on experiments 

 conducted by Dr. Bail, of Prussia, many years ago. The following ex- 

 tract illustrates the ground taken in the article : 



Dr. Bail asserts tliat he has proved by many skillful esperitnents that four species 

 of microscopical fungi are merely dilferent 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 cov- 

 ered by a white moldnot easy to be removed. The second is the common mold, known to 

 everybody and easily 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 fermen- 

 tation. The foiirth is a small \\ ater plant, known only to iirolessional botanists. Dr. 

 Bail contends that the spores of the fungus of the house fly develop in water this last- 

 species, out of v,ater tn mold, and that the seeds of mold are transformed in the mash 

 tub mto yeast fungus. 



The experiments made by Dr. Bail cover a period of more than a dozen years, since / 

 the num(-roiis results which were made against his results induced him to rejjeat again 'V-- 

 and again his experiments in dilferent 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 

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

 proved that mold 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 illus- 

 trated by the exhibition of mold 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 tlus 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 

 pS^I)ared without the fungus of the house 2y. 



Although modern mycologists do not believe in the identity of the 

 fungi mentioned, I considered the matter of sufficient importance to be 

 the subject of further investigation. I therefore instructed Mr. Tre- 

 lease to make the proper experiments to ascertain if yeast torulae sown 

 on insects would give rise to a fungus which would cause their death. 

 The following is the report of these experiments. Care was taken in 

 every instance to see that the yeast was in an active state. 



August 1, during a light shower, I applied a gallon of yeast in eight gallons of 

 water to cotton on which there were many half-grown caterpillars, as well as num- 

 bers of small ones, using a fountain-pump for distributing the liquid, and being care- 

 ful to reach all parts of the cotton with it, wetting it, indeed, so thoroughly that the 

 air for some distance was pervaded by a yeasty odor. Before I had" finished the 

 shoAver became heavier, and it rained hai'd for a considerable part of the night. There 

 was more or less rain nearly every day for the succeeding week. Examination every 

 few days showed that no fungus was attacking the worms. 



August 7, I applied several gallons of water in which was yeast in proportions vary- 

 ing from one-half pint to one quart to the gallon of water. This was applied in the 

 morning while the sun was shining brightly, and no rain fell on it until night, though 

 more or less rain fell every day for the next half week. There were worms of aU sizes 

 where this was used, but none were attacked by disease. 



August 13, more was applied in varying quantities of water, the day being cloudy, 

 but only negative results were obtained. 



*The Pyrcthntm cina'ariacfolium was introduced into California and is raised by Mr. 

 G. N. MUco, of Stockton, Cal. 



