STUDIES IN THE PHYSIOLOGY OF SPERMATOZOA. 205 



but by increase in the concentration of bivalent ions, notably 

 calcium (Loeb, J., 1914). Unlike "agglutination" it is not rever- 

 sible. In an earlier paper Lillie did not distinguish between the 

 two phenomenon, for he wrote: "Agglutination is not in itself a 

 specific process; it may take place spontaneously to a certain 

 extent under some conditions; it is caused by increase of alkalinity 

 of the sea-water" (Lillie, F. R., 1913, p. 563). Loeb has desig- 

 nated Lillie's "agglutination" as "cluster formation." 



It will be remembered that increasing the alkalinity also in- 

 creases the activity of spermatozoa. Loeb (1914) has shown that 

 inactive sperm do not exhibit the reversible "agglutination." 

 The irreversible agglutination, or "mass coagulation" is inde- 

 pendent of the motility of the spermatozoa. 



If the "egg water' is of sufficient strength, 2 however, the 

 sperm are completely non-motile after the initial period of activa- 

 tion. By adding eggs to such spermatozoa Lillie showed that 

 their fertilizing power was slight. 'The powerful effect of the 

 egg extract on spermatozoa of the same species may be shown by 

 a complete loss of motility as we have already seen, and also by a 

 corresponding loss or diminution of the fertilizing power" 

 (Lillie, F. R., 1913, p. 558). 



Fuchs (Fuchs, H. M., 1915) in experiments in which sperm that 

 had been treated with "egg water" were added to eggs in sea- 

 water showed that the fertilizing power of the sperm had been 

 increased by the "egg water." 3 



But an analysis of the effect of "egg water" upon the fertilizing 

 power of spermatozoa must differentiate between the following 



1 That "agglutination" is reversible may possibly be attributable to an increase 

 in the acidity of the clusters; the result of the carbon dioxide produced by the 

 tremendously active spermatozoa. In alkaline medium the carbon dioxide would 

 be neutralized. 



2 In the measurement of the strength of "egg water" the method of F. R. Lillie, 

 (namely considering that dilution of "egg water" that gives a visible "agglutina- 

 tion" as unity), is adopted. Reference is made to the papers of Lillie, F. R., and 

 Fuchs, H. M., for a detailed description of the methods and precautions employed 

 in this type of experimentation. 



3 According to T. B. Robertson, "when spermatozoa are washed in 3/8 M SrCb 

 and then in blood serum, they gain an added potency in fertilizing." (Robertson, 

 T. B., 1913, p. 128.) The same treatment agglutinates (ibid., page 71) (and also 

 cytolyzes) (ibid., p. 91) the eggs of the sea urchin. 



