'58 



MARTIN FROBISHER, JR. 



The growth on a Buchner flask was suspended in 50 cc. of 

 water and left in the incubator for four days. None of the color 

 was imparted to the water. It was found that no pigment could 

 be extracted from the intact cells with ether, alcohol, chloroform, 

 glycerine, or water. Nor was any to be obtained with these 

 solvents after grinding the dried cells with sand. 



Simultaneously with these cultural studies, attempts were 

 being made to determine what had killed the flies in the original 

 jars. 



Pure cultures were made of the red torulse and of the Penicil- 

 lium-like mold in suitable flasks, and anaesthetized flies were 

 introduced. The first three experiments are summarized in 

 Table I. The red torula alone has since been used successfully 

 to rear several vigorous batches of flies. 



TABLE I. 



FATE OF FLIES FED ON PURE CULTURES OF RED TORULSE AND Penicillium 



RESPECTIVELY. 



(Three experiments.) 



1 No observation. 



It has already been pointed out that the combined growth 

 of torulac and mold results in the formation of a hard tough mass. 

 This led to the idea that the mold might kill the flies by growing 

 among the yeast cells in the alimentary passages and thus block 

 elimination and engorgement. It was found that a combination 

 of the mold, and of the commercial yeast upon which the flies 



