STUDIES IN ARTIFICIAL PARTHENOGENESIS. 177 



acid to 50 c.c. of sea- water. Of this solution, 5 c.c. \vas put 

 into each of t\vo Syracuse watch-crystals A and B. 



To A were added 5 c.c. of sea- water and five drops of egg 

 suspension. 



To B were added 5 c.c. of filtered blood (from several cf s and 

 9 s) and then 5 drops of egg suspension. 



The result of the experiment was that in A the vitelline mem- 

 branes swelled in practically every case. A count of a hundred 

 eggs gave ninety-nine eggs with swollen membranes and the 

 single exception was doubtful. On the contrary, there was 

 practically no membrane swelling in B, which contained blood 

 in addition to the acid. A count gave, of a hundred eggs ob- 

 served, only three with swollen membranes. 



The inhibiting effect of blood upon acid swelling, unlike the 

 effect of cyanide on salt swelling, may perhaps be the result 

 of a direct action of the blood upon the acid. This is barely 

 suggested by the fact that N/io HC1 produces a flocculent white 

 precipitate when added to filtered sea-urchin blood. However 

 in the above recorded experiments with butyric acid, no such 

 precipitation could be observed. 



Instead of exhibiting a retarding effect upon membrane 

 swelling by salts, sea-urchin blood seemed to favor the process. 

 This favorable effect was much more pronounced in some cases 

 than in others, and in several experiments it was not readily 

 observed. On July 28, 1914, membrane swelling was found to 

 be much more rapid and pronounced in a solution of 20 c.c. 

 sea-water plus 5 c.c. filtered blood (from 9 s) plus 4 c.c. 2.5 

 M NaCl, than in a similar solution without blood, i. e., 25 c.c. 

 sea- water plus 4 c.c. 2.5 M NaCl. It sometimes happens, and 

 this appeared to be more frequent in 1914 than in 1913, that 

 membrane swelling does not occur in "NaCl hyper tonic sea- 

 water." In such cases, it was found possible in several instances 

 to produce a membrane swelling by the addition of blood. Thus 

 on July 30, 1914, although there was no swelling in "XaCl 

 hypertonic sea- water," when eggs of the same lot were placed 

 into 5 c.c. blood plus 20 c.c. sea- water plus 4 c.c. 2.5 M NaCl 

 membrane swelling did occur. 



It might be reasoned that this action of blood is analogous 

 to the cytolytic effect of sera foreign to the individual. But 



