MALE-PRODUCTION IN HYDATINA 



139 



Effect of dilute bouillon 



Experiment 12. The bouillon solution used in this experiment was 

 made from one cube of Armour's beef bouillon in 21,000 cc. of water. 

 As nearly as we could compute from Whitney's paper, this was the 

 concentration of bouillon present, in his cultures after the rotifers 

 had been fed with Chlamydomonas. Two lines of rotifers, derived 

 from sisters, were reared, one in spring water, the other in this dilute 

 bouillon solution. Table 9 shows a slight reduction in the numlier 

 of male-producers in bouillon, rather than an increase. 



TABLE 9 



Showing the effects of continuous rearing of Hydatina in a dilute bouillon solution. 

 The number of male-producers (cf 9 ) is slightly decreased 



Experiment 13. Bouillon was tested in this experiment by rearing 

 only the parents in bouillon, not their offspring. This was VVTiitney's 

 method in working with Chlamydomonas, and was based on Maupas's 

 statement (1891), subsequently confirmed by Shull ('12), that the de- 

 termination of the sex of an individual takes place in the body of its 

 grandmother. The concentration of the bouillon was made less than 

 that in Experiment 12, being one cube in quantities of water varying, 

 on different days, from 30,000 to 80,000 cc. Two lots of females of 

 approximately equal size and from the same source were set aside 

 on the same day, the one in spring water, the other in bouillon solution. 

 The parents were removed after 24 hours. The offspring from all 

 eggs laid in that time were reared to maturity in spring water, and 

 recorded. In table 10 the nature of these offspring is summarized. 

 Here again there is a slight reduction in the number of male-producers 

 in bouillon solution. The consistent results of these two experiments 

 seemed to make it not worth while to look for a male-producing factor 

 in the dilute bouillon solution used by Whitney. 



