276 



MYRA M. SAMPSON. 



Effect of Dilution on Hctero-agglutmating Power of Solu- 

 tions. Lillie (1915) found in the case of hetero-agglutinins in 

 Arbacia egg-water a disproportional loss of agglutinating power 

 with dilution, and certain preliminary experiments with one half 

 and one fourth dilutions of solutions of cytolyzed spermatozoa of 

 S. purpuratus indicated a similar loss. The results obtained with 

 a series of greater dilutions are indicated in the following table : 



TABLE II. 



THE EFFECT OF DILUTION ON STRENGTH OF HETERO-AGGLUTINATION OF SOLU- 

 TIONS OF CYTOLYZED SPERMATOZOA OF S. purpuratus. 



In the above summary the decrease in agglutinating power 

 appeared to be associated with a decrease in activating power of 

 the diluted solution of cytolyzed spermatozoa. One might predict 

 that an activating substance added to cytolyzed sperm solutions 

 would prevent the loss of agglutinating power. This actually 

 proved to be true, for upon the addition of an activating body a 

 dilution of 1/60 produced as intense and immediate activation and 

 pinwheel formation as the undiluted solution. 1 



B. Effect of the Blood of S. purpuratus and S. franciscamts. 



Filtered blood of both male and female 6". purpuratus and S. 

 franciscanus causes activation and hetero-agglutination of sperma- 

 tozoa of K. tunicata exactly like that produced by solutions of 

 cytolyzed spermatozoa of S. purpuratus. The blood must, how- 

 ever, be taken from the animals on the day on which they are 

 taken from their habitat. Otherwise it will produce activation, 

 but no agglutination. This is comparable to the deterioration of 



i The substance in question will be discussed in a subsequent paper. 



