432 MARIE A. HINRICHS. 



be reactivated, but not reagglutinated. Sperm treated with egg- 

 water which had been strongly radiated become inactive, but may 

 be reactivated by normal egg-water and to some extent reaggluti- 

 nated. The sperm exudate had apparently not been entirely 

 " fixed " by the egg-water, even though the sperm had become in- 

 active. This is further evidence of the presence of two substances 

 in egg-water, one responsible for activation, and the other for ag- 

 glutination of sperm. Two other bits of evidence cited above also 

 bear out this suggestion. Radiation may remove the agglutinat- 

 ing power of a given sample of egg- water, yet it may still retain 

 its power to activate sperm. Also, egg-water adsorbed on char- 

 coal does not lose its activating power, for when the charcoal and 

 egg-water mixture is washed with sea-water, and the filtrate added 

 to fresh sperm, the latter are activated but not agglutinated. Ap- 

 parently the activating component of egg-water is not adsorbed by 

 charcoal, or less so than the agglutinating component. 



The colloid components of egg- water are best adsorbed within 

 an optimum pH range which hovers about the point of neutrality. 

 Recovery by acid is possible, and increasing the acidity of the egg- 

 water beyond the optimum range, lowers its adsorbability by char- 

 coal. This may depend on a reversal of the charge carried by the 

 fertilizin particles, but further experimentation on this point is 

 necessary. Saponin does not displace the fertilizin from adsorp- 

 tion. Radiation of fertilizin causes a slight increase in acidity. 

 This is in accord with the findings of Stedman'and Mendel, '26, 

 for protein solutions and distilled water. 



The echinochrome pigment in egg-water is faded by ultraviolet 

 radiation. Its function is a rather uncertain one. Glaser, '210, 

 suggested that this substance acts as a stabilizer for fertilizin. It 

 has been found to have a certain amount of photodynamic activity. 

 (See R. S. Lillie and Hinrichs, '23.) The pigment is also ad- 

 sorbed by charcoal, as shown in the above experiments, and by 

 Glaser in 1921. (Glaser, '21 a.) It is probably colloidal in na- 

 ture. 



The production of fertilizin by mature eggs has been discussed 

 above at greater length. F. R. Lillie associates fertilizin produc- 

 tion with viability of eggs as follows, " When an egg ceases to 

 produce the sperm-agglutinating substance, it has lost its capacity 



