424 Journal of Agricultural Research voi. xvni, No. s 



vegetate more freely, so that at the end of one month cultures left in the 

 laboratory showed nearly as luxuriant a growth as those retained in the 

 water cooler. 



The results of these tests indicate a preference of Sorosporella for 

 temperatures varying from 18° to 22° C. ; and the fact that such lower 

 temperatures are preferred is not surprising, since the fungus under 

 natural conditions grows in insects which are rarely exposed to heat 

 above 22°, cutworms, for example, being exposed to the air only at 

 night when it is cool, and resting during the day under boards or other 

 debris where the temperature is somewhat lower than in more exposed 

 places. 



The fact that the natural vegetative development of the fungus occurs 

 within a liquid menstruum, insect blood, the aeration of which is supposed 

 to be more or less complete through the respiratory action of the tracheae, 

 led to attempts to cultivate it in artificial liquid media, in certain tubes 

 from which the air was largely removed or replaced by another gas. 



In fermentation tubes of Molisch's solution to which the air had free 

 access, however, no gas formation could be detected; but yeastlike 

 vegetative cells were formed abundantly, which were quite similar in 

 size and form to those formed within living insect blood. With the 

 exception of soft Uschinsky's agar and soft Molisch's agar, no other 

 nutrients have been found upon which the fungus vegetates typically 

 by blastocysts ; and it seems probable that such a type of development 

 is aided by and perhaps even dependent upon a liquid, or at least a 

 very wet substratum. In addition to the blastocysts which occurred 

 within the nutrient solution and at some distance from its surface, a 

 complex of mycelium filaments, composed of slender, threadlike, sep- 

 tate, sinuous hyphse, as well as thick filaments with large barrel-shaped 

 cells, was formed at the surface of the solution. The slender, sinuous 

 threads gave rise to conidiophores and conidia; but the thick, barrel- 

 shaped cells first formed spherical, red-colored resting spores, although 

 these bodies later germinated, giving rise to conidiophores and conidia. 



To determine whether or not the organism would grow in a partial 

 vacuum, Molisch's solution was placed in ordinary test tubes into which 

 pieces of glass tubing led through perforated rubber corks. The glass 

 tube was then heated about half way from either end and drawn out 

 until it was considerably constricted. The exposed end of the glass 

 tube was then closed with a cotton plug. After sterilization such test 

 tubes were inoculated, and a water pump was attached to the glass 

 tubing with a wash, bottle interposed. By allowing the pump to work a 

 few minutes a sufficient amount of air was removed from the test tube 

 to render a fair vacuum. When this was accomplished the constricted 

 portion of the glass tube was rapidly sealed and divided by the appli- 

 cation of a Bunsen flame. Several tubes were treated in this manner, in 

 none of which was there at any time afterward any apparent growth of 



