PHYSIOLOGY OF THE SPERMATOZOON 113 



spermatozoa are then for a time relatively immobile. 

 The same observations were also made on Nereis. Loeb 

 (1914)' has reported the occurrence of the same phe- 

 nomenon in various species of sea urchins, Glaser (1914) 

 in Asterias, and Just (1918) in Echinarachnius. 



The drop of egg water, two to four millimeters in 

 diameter, may be regarded as equivalent, in a chemical 

 sense, to a much magnified egg, and the reactions of 

 the spermatozoa to it as similar to reactions to the 

 actual egg, with this exception, that the solid surface is 

 lacking. We see here three kinds of effects of the spe- 

 cific egg water, viz., activation, aggregation, and aggluti- 

 nation. 1 The aggregation effect evidenced by the ring 

 and clear zone with reference to the introduced drop is 

 entirely similar to the aggregation of spermatozoa of 

 Nereis produced by CO 2 and other acids. In the case 

 of the egg water it is complicated by simultaneous 

 agglutination; but it is possible to eliminate the agglu- 

 tination effect (Lillie, 1913) by neutralizing the agglu- 

 tinating substance and to leave the aggregating effect 



1 The term "agglutination" will be used exclusively for this revers- 

 ible phenomenon of adhesion of living cells for a longer or shorter 

 tune. Agglutination in this sense has no effect destructive of the life 

 of the spermatozoon, toxic or otherwise. This seems to the author a 

 correct biological use of the term. Certain other substances, such as 

 KOH, NaOH, or certain fluids of other species, cause an irreversible 

 sticking together of spermatozoa, which is obviously a different phenom- 

 enon biologically and is usually destructive. This is to be distinguished 

 sharply from biological agglutination. Confusion is likely to arise in 

 the use of the term, because Loeb, for instance, has called the caustic 

 alkali effect "real sperm agglutination " (1914, pp. 126-27). He is 

 here using the term in its etymological significance. The effect of 

 caustic alkalies is also strikingly different in appearance; anastomosing 

 cords of sperm are formed constituting a network; the strands never 

 contract into spheres as in agglutinated sperm; moreover, the sper- 

 matozoa are motionless and evidently dead. 



