igii] 



A. Franklin Shull 



179 



due was extracted witli ether for twelve hours, after which the 

 ether was filtered through paper and the Solution evaporated to 

 dryness. Less than 0.0 1 gram of ether-soluble siibstances was 

 thus obtained. It did not seem likely that so small a quantity would 

 have any noticeable effect on the proportion of male-producers, 



TABLE 3. 



Showifig the nnmber of male- and fcmale-producers in the progeny of three 

 sister individtials of Hydatina senta, one line being reared in the filtrate of old 

 food culttires that had been dried and redissolved, one in boiled filtrate, and one 

 in spring water. 



but the experiment was nevertheless made. This ether-soluble 

 residue was dissolved in 125 c.c. of distilled water, giving a color- 

 less Solution, and a line of rotifers was reared through four gen- 

 erations in it. The residue after ether-extraction was likewise 

 dissolved in 125 c.c. of distilled water and boiled, making a brown 

 Solution not apparently different from the original manure culture, 

 and a sister line of rotifers was reared in the Solution. A third 

 line was reared as control in spring water. Table 4 shows the 

 result. 



The experiment was so brief that the difiference in the proportion 

 of male-producers between the line in spring water and that in the 

 ether-soluble part of the filtrate may mean nothing. The chance 

 of obtaining any result from such a minute ether-soluble residue 

 did not seem to Warrant a more extensive experiment, especially 

 since the part of the manure Solution not soluble in ether had the 

 same effect as the entire manure Solution had in other experiments. 



