490 



ALVALYN E. WOODWARD 



Since the inhibitor present in the egg is a compound of an 

 unsaturated fatty acid, iodine should saturate the acid and enable 

 the egg to develop. The validity of this reasoning is shown by 

 experiments in which Miss Hague and the writer ('17) used 

 iodine as a parthenogenetic agent with Arbacia eggs. The 

 curves in fig. 2 and the data in table 16 summarize the results by 



TABLE 15 



The effect of salt solutions on resistant Asterias eggs. The amount of reagent indi- 

 cated in the first column was added to 100 cc. sea-water. The eggs icere treated 

 with these solutions for twenty minutes, washed, and inseminated 



Note. — The addition of very dilute KCNS (about 1 cc. of a 1 per cent solution 

 to 100 cc. of sea-water) likewise produced a great increase in the number of eggs 

 fertilized. 



giving the average number of cleavages obtained by each method 

 of treatment. The fact that the length of time during which the 

 eggs are subjected to iodine does not affect the number of cleav- 

 ages, indicates that the reagent not only enters the egg imme- 

 diately, but also affects it immediately to its fullest extent. 

 This strengthens the idea that iodine accomplishes its result by 

 combining with the unsaturated fatty inhibitor. The membranes 



