348 Illinois State Laboratory of Natural History. 



in the course of two days; and with further growth a 

 slight film is developed on the surface, and a precipitate 

 begins to accumulate at the bottom. This precipitation 

 increases with the maturity of the culture, the superficial 

 film disappears, and the liquid is left slightly clouded 

 and very little darker than the uninoculated fluid. After 

 the cessation of growth, there is no further change of 

 color in the bouillon. Other cultures were made on de- 

 coctions of green corn, of squash leaves, and also on 

 a mixture of bouillon with each of these. The growth 

 differed little from that on bouillon, except in a thicker, 

 scum-like surface film. 



Sterile skimmed milk inoculated from a pure culture of 

 the squash-bug bacillus shows considerable curdling in 

 twenty-four hours, and subsequently a rapid production 

 of whey. In one week the curd is about half dissolved, 

 and it soon assumes a somewhat rusty color, as also 

 does the turbid whey. A few da^^s after inoculation the 

 odor from these milk growths is extremely disagreeable* 

 and it becomes vile and penetrating. It resembles the 

 odor of sulphureted hydrogen, and, while not so strong, 

 it is more nauseating. An infusion of the bacillus from 

 a growth on agar was sterilized at a low temperature, 

 and then added to a small quantity of sterile skimmed 

 milk. No change was produced in the milk, and a sub- 

 sequent inoculation with the active bacillus gave a growth 

 characterized as above. 



From the experiments recorded under the head of 

 "Toxic Properties" it is noted that an infusion* of this 

 organism from an agar culture contains some substance 

 fatal to insects, and various media were "employed in 

 order to get this substance in a form suitable for chem- 

 ical analysis. Buckmastert has mentioned some nutrient 

 media used by Uscliinsky for the cultivation of certain 



* It is well to noto here that in this paper I have used (hn- word infusion ouly 

 to denote the fluid in which bacferia have been diftu'^ed for inoculation or other 

 such purpoi-CF, and no Idea of heat is thereby imidied. 



t Urxprung und liei^chaffenhell gewisser JJakteriengifle. (Biol. Centr. Bd. 

 XV.. Nr.i, Feb.. 18'J5. 



