208 



EFFECT OF ENVIRONMENT ON FACET NUMBER 



the acidity, I tried raising mass cultures on pure Fleischmann's yeast 

 made into a paste and covered with cotton-wool. To my surprise 

 the cultures hatched 1 day earlier than did the banana control and an 

 examination of the facet counts showed an appreciable difference in 



TABLE I. 



Effect of Temperature upon Facet Number in the Ultra-Bar Mutant of Drosophila 



melanogaster. 



TABLE II. 



Effect of Various Foods upon Facet Number in the Ultra-Bar Mutant of Drosophila 



melanogaster. 



the mean. A repetition of the experiment at 23 and again at 27°C. 

 gave consistent results. What the actual factor is that underlies this 

 phenomenon is still uncertain. The data are given in Table II. 



Humidity has been one of the factors to receive considerable atten- 

 tion in the past few years. Since the apparatus for humidity and 



