BIOLOGY OF SPERMATOZOA 



spenn toward it. The iihenomenon of chemo- 

 taxis has, however, been established as oc- 

 curring in some primitive ph^nts, such as 

 certain ferns, mosses, and brown algae, and 

 the various attempts to determine the na- 

 ture of the chemical stimulus and the mech- 

 anism of the response have been attended by 

 some success (Pfeffer, 1884; Shibata, 1911; 

 Cook, Elvidge and Heilbron, 1948; Cook 

 and Elvidge, 1951; Rothschild, 1951b, 

 1956b; Wilkie, 1954; Brokaw, 1957, 1958a, 

 b). 



Activation of sperm by homologous eggs 

 and egg exudates has been described in some 

 invertebrate species, and the stimulating ac- 

 tivity has been attributed to the fertilizin 

 (gvnogamone I) present in the egg jelly 

 coat (Lillie, 1919; Tyler, 1948; Rothschild, 

 1956b). The source of the activator and the 

 specificity of the reaction are, however, 

 somewhat controversial. The increase in 

 motility, when observed, may or may not be 

 accompanied by a substantial enhancement 

 in respiratory activity (Rothschild, 1956b). 



The species-specific agglutination of in- 

 vertebrate spermatozoa by fertilizin of ho- 

 mologous eggs constituted the keystone of 

 the fertilizin theory advanced by Lillie 

 (1919) to account for the specificity and 

 "cell recognition" inherent in the process of 

 fertilization. The nature of the serologic- 

 like gametic substances — egg fertilizin and 

 sperm antifertilizin — and the role these sub- 

 stances may play in the fertilization process 

 have been extensively studied by Tyler 

 and coworkers (1948-1959). Sperm aggluti- 

 nation by egg exudates has been demon- 

 strated in many species of animals in both 

 the invertebrate and lower vertebrate groups 

 (see Tyler, 1948). The phenomenon is also 

 exhibited by mammalian gametes (Fig. 

 13.19), among which some degree of species 

 specificity is displayed (Bishop and Tyler, 

 1956 ) . A current view of the possible signifi- 

 cance of these gametic substances to fertili- 

 zation may be found in the recent review by 

 Tyler (1959). 



Spermatozoa not only seem to interreact 

 serologically with egg exudates resulting in 

 agglutination and/or loss of fertilizing ca- 

 pacity; they also can be stimulated under 

 some circumstances to undergo morphologic 

 change, most spectacularly characterized by 



the acrosome reaction (Dan, 1952, 1956; 

 Colwin and Colwin, 1955, 1957). The forci- 

 ble release of material from the sperm head 

 (Fig. 13.20), apparently induced by the 

 presence of egg fertilizin, involves the pro- 

 trusion of a filamentous projection which 

 seems to play a vital, if, as yet obscure, role 

 in the initial stage of the fertilization proc- 

 ess. 



XI. Conclusion 



The notation of a conclusion to the Biol- 

 ogy of Spermatozoa seems singularly in- 

 appropriate. Both the intensity and the ex- 

 panse of current research indicate that one 

 is merely taking stock of accumulating data 

 and transient concepts — that in the future 

 lies the answer to most of the ciuestions 

 raised in the pages above. On the one hand, 

 the properties of spermatozoa can be ex- 

 pected to become increasingly clear by our 

 delving more deeply into the nature and ac- 

 tivity of the cell, a fruitful approach in its 

 own right and beneficial to the more practi- 

 cal concerns of fertility, sterility, and ani- 

 mal breeding. On the other hand, the recog- 

 nition of the general characteristics of sperm 

 behavior, movement, metabolism, and sur- 

 vival seems likely to shed brighter light on 

 comparable processes and systems in other 

 cells and tissues, including the nature of cell 

 regulation and adaptation, energy utiliza- 

 tion, aging, and movement inherent in 

 ciliary activity, flagellation, and muscular 

 contraction. 



If much of the foregoing seems more frag- 

 mentary than complete, more provocative 

 and speculative than dogmatic or resolute, 

 this survey may then serve some purpose. 

 The accomplishments have been many, but 

 even more fascinating developments lie 

 ahead. 



XII. References 



Abarbaxfx, a. R. 1946. Spermatozoa and cer- 

 vical mucus. In The Problem of Fertility, 

 E. T. Engle, Ed. pp. 119-126. Princeton, X. J.: 

 Princeton University Press. 



Abarbanel, a. R. 1948. Artificial reproduction 

 of the cyclic changes in cer\'ical mucus in 

 human castrates, with clinical correlations. 

 West. J. Surg., 56, 26-34. 



Adams, C. E. 1956. A study of fertilization in the 

 rabbit: the effect of post-coital ligation of the 



