154 MARTIN FROBISHER, JR. 



Material from the jar was therefore plated out on a medium 

 similar to that used for the fly cultivation. 1 To obtain the 

 inoculum, a piece of the tough, yellow membrane covering the 

 surface of the agar in the fly bottle, under the growth of the 

 mold, was cut out with a loop of stiff sterile wire. The under 

 side of this piece of membrane was carefully scraped and the 

 scrapings spread upon the medium in petri plates. Smears of the 

 scrapings were made at this time, and stained with Gram's stain 

 and with Loeffler's methylene blue. These preparations showed 

 the presence of mold hyphse, spores and yeast cells. No bacteria 

 were seen. This is readily understood in view of the acidity of 

 the medium. 



Plates streaked as above were incubated in the refrigerator 

 at about 6 C., also in the laboratory at a temperature of about 

 25 C., and other plates were held at 37 C. Growth occurred 

 at all three temperatures, but most abundantly and rapidly on 

 the plates held at about 25 C. On all plates there appeared 

 nothing but the white commercial yeast referred to and the 

 mold. There was no yellow growth on any of the plates, even 

 after long standing at different temperatures and in the dark as 

 well as in the light. 



The attempt was regarded as a failure, since no organism 

 appeared except those believed to be harmless to the flies. A 

 second and third attempt yielded like results. No yellow organ- 



1 This medium is prepared as follows: 

 Solution A. 



Water Distilled 500 cc. 



Sucrose 83.5 grams 



CaCh 25 " 



MgS0 4 50 " 



(NH 4 hSC>4 2.00 " 



KH 2 P0 4 i.oo " 



Tartaric Acid 5.00 



Rochelle Salt 8.40 " 



Solution B. 



Water Distilled 500 cc. 



Agar 30 grams 



Autoclave A and B separately. Mix aseptically in equal parts just before use. 

 The solutions keep well separately. The reaction is about pH 3.2. 



