242 CLAUDE W. MITCHELL 



dividuals likewise from poorly nourished parents themselves 

 subjected to high nutrition without starvation also gave negative 

 results. Individuals from well-nourished parents themselves sub- 

 jected to high nutrition without starvation give but 11 per cent 

 of male producers. Individuals from well nourished parents, 

 subjected to starvation at birth, followed by a period of high 

 nutrition gave seventy per cent of male producers. Although 

 the numbers employed in this experiment are insufficient to fully 

 warrant general conclusions, yet they form valuable confirma- 

 tion of the preceding results. The first and most fundamental 

 condition for male-production is plainly a high-potential grand- 

 parent which will transmit its high potential under good food con- 

 ditions to its progeny. It can be obtained from a generation 

 in the crescendo of the metabolic rhythm. The second though 

 hardly less important factor is a slight nutritive interruption or 

 period of starvation in the generation of potential male-producers 

 itself. This conclusion suggested the attempt to determine still 

 more definitely the period at which starvation is effective. Such 

 experiments would of course serve at the same time as further 

 test of the conclusions reached. 



EFFECT OF STARVATION AFTER THE INITIAL GROWTH PERIOD OF 



THE FIRST EGG 



Thirty young individuals of the humped type were chosen from 

 pedigree lines in high crescendo and were isolated in a culture 

 containing food in such quantity that a nonxial supply could be 

 obtained by each individual. These young were allowed to re- 

 main in this culture while the first egg began to appear growing 

 at the apex of the ovary. Each individual, about the time the 

 connection of .the egg with the ovary was broken, was isolated 

 in a typical starvation culture where it was kept without food 

 for a period of eight to ten hours. Food was then given. As 

 table 7 shows, there resulted but 30 per cent of male producers, 

 only a moderate increase over the per cent in the normal well 

 fed series of humped individuals. 



