222 HELEN DEAN KING. 



according to Loeb ('06), both these substances cause eggs to 

 absorb water, the quantity of water taken up increasing with the 

 quantity of acid or of alkali used. 



Of the many preliminary experiments made in the spring of 

 1909, only one gave results that could be considered of any value. 

 In this case one lot of eggs was artificially fertilized in a .01 per 

 cent, solution of hydrochloric acid: another lot of eggs from the 

 same female was fertilized with spermatozoa from the same male 

 in a .01 per cent, solution of ammonium hydrate. In each case 

 the eggs remained in the solution for one half hour, and were then 

 transferred into fresh water. The mortality in both lots of eggs 

 was very high, and was probably at least 50 per cent. No record 

 was made of the number of individuals with which the experiment 

 was started. The results obtained are indicated in Table V. 



TABLE V. 



EGGS FERTILIZED IN A SOLUTION OF ACID OR OF ALKALI. 



The percentage of females obtained from the lot of eggs that 

 was fertilized it the acid solution is somewhat low, yet one 

 might attribute it to a chance variation in the sex ratio: the 

 percentage of females obtained in the lot of individuals derived 

 from eggs that were fertilized in the alkaline solution is but 

 slightly greater than that in the control, and therefore calls for 

 no comment. These results afford little evidence that the sex 

 ratio of Bufo can be altered by subjecting the eggs to environ- 

 mental conditions at the time of fertilization that might cause 

 them to absorb a greater amount of water than usual. 



Hydrochloric acid is inorganic, and ammonium hydrate is 

 known to have a very injurious action on developing eggs. It 

 was thought, therefore, that possibly different results might, 

 be obtained if eggs were fertilized in solutions of other sub- 

 stances. The experiments were repeated on a much larger 

 scale this past year; acetic acid and sodium hydrate being 



