ULTRAVIOLET AND ARBACIA FERTILIZATION. 



4 2I 



only a 6 per cent, reduction of color loss appears during the same 

 period. In this case, 68 cc. of dry eggs were covered with enough 

 sea-water in a graduated cylinder to reach the 250 cc. mark. The 

 suspension was allowed to stand for 3 hr. before the egg-water 

 was decanted off. This egg-water was then exposed to radiation 

 for varying periods of time, and its agglutinating power tested 

 against a i per cent, sperm suspension. In each case, the final 

 agglutinating dilution was noted. (See Table IV.) 



TARLE IV. 

 THE EFFECT OF RADIATION ON THE AGGLUTINATING POWER OF EGG- WATER. 



Prolonged radiation of egg- water prevents the activation and 

 agglutination of sperm, and may even produce a lethal effect on 

 sperm. When radiated egg-water is added to normally aggluti- 

 nated sperm, the clusters become " loose " and permanent, and the 

 sperm inactive. Sperm inactivated by radiated egg-water may be 

 reactivated by normal egg-water, so that normal but small, re- 

 versible clusters may form. 



The agglutinating power of a given sample of egg-water may 

 have been entirely lost following radiation, yet the same sample 

 may still be capable of stimulating sperm to greater activity. 

 Either the sperm-stimulating and sperm-agglutinating substances 

 are not identical (Lillie and Just, '24, p. 483) or a lesser amount 

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