34 FERTILIZATION 



Rothschild (195 1). To sum up, there is no doubt that egg water 

 does in certain circumstances stimulate spermatozoa to increased 

 and more prolonged movement and metabolism. Whether this is 

 due to a substance which is not the same as fertilizin is an open 

 question. The protein carrier and ternary complex story should 

 not be accepted until it is independently confirmed. 



Inhibition of sperm agglutination by egg and sperm extracts. F. R. 

 Lillie suggested in 19 14 that a substance which could neutralise 

 fertilizin was present in sea-urchin eggs. This substance, called 

 antifertilizin or egg-antifertilizin, was extracted from sea-urchin 

 eggs by Runnstrom (19356) and Tyler (1940^). Using the gamone 

 terminology, antifertilizin would be called G.III or, if one wanted 

 to be pedantic, Gynandrogamone I, as it can be extracted from 

 eggs and spermatozoa. Both egg- and sperm-antifertilizin inhibit 

 the action of egg water and, in suitable conditions, precipitate 

 fertilizin ; they make unfertilized eggs of the same species agglu- 

 tinate and induce the formation of a membrane-like structure, 

 usually known as a precipitation membrane, on the surface of egg 

 jelly. The latter is somewhat similar to the Neufeld reaction of 

 pneumococci and other encapsulated bacteria reacting with 

 specific antisera. If fresh eggs are extracted by freezing and thaw- 

 ing, no antifertilizin is obtained, because it is neutralised by the 

 fertilizin in the jelly present round such eggs. Injection of egg- 

 antifertilizin into rabbits induces the production of antibodies 

 which precipitate antifertilizin and agglutinate homologous 

 spermatozoa (Tyler, 1948, p. 202). 



A substance with very similar properties can be extracted by 

 heating (Frank, 1939), freezing and thawing (Tyler, 1939), and 

 acidification (Tyler & O'Melveny, 1941) from spermatozoa, 

 Table 5 ; it also is called antifertilizin and is the substance with 

 which fertilizin is believed to combine, causing agglutination. It 

 is evident from what has been said immediately above that there 

 is an antigenic complementarity between sperm-antifertilizin and 

 the antibodies formed in rabbits following injection of egg- 

 antifertilizin. 



There has been some discussion as to whether sperm-anti- 

 fertilizin is an acidic protein, as stated above, or, as Hultin (1947) 

 thinks, an unspecific basic protein derived from sperm nuclei. 

 The latter induces the formation of a precipitation membrane on 

 egg jelly and causes homologous sperm agglutination (Metz, 1949), 



