990 THE PHYSIOLOGY OF REPRODUCTION. 



vagina in the female and thus prevent the loss of the fertilizing 

 liquid. The union of spermatozoon and ovum is believed to 

 take place usually in the Fallopian tube, and under normal con- 

 ditions only one spermatozoon penetrates into the egg. The 

 remainder of the great number that may be present eventually 

 perish. The changes that take place during the process of fer- 

 tilization have already been described (p. 976). 



Chemistry of the Spermatozoa. Much chemical work has 

 been done upon the composition of spermatozoa, particularly in 

 the fishes. The results have been most interesting from a chem- 

 ical standpoint, and biologically they are suggestive in that the 

 analytical work has been done upon the heads of the spermatozoa. 

 These heads consist entirely of nuclear material, and contain the 

 substance or substances which convey the hereditary characteristics 

 of the father, or, to speak more accurately, of the race to which the 

 father belongs. Whatever progress may be made in the understand- 

 ing of the chemistry of this material is a step toward the solution of 

 the most difficult and mysterious side of reproduction, the power 

 of hereditary transmission. Miescher, in investigations upon the 

 spermatozoa of salmon, discovered that the heads are composed 

 essentially of an organic combination of phosphoric acid, since 

 designated as nucleic acid, united with a basic albuminous body, 

 protamin. This view has been confirmed and extended by later 

 observers, especially by Kossel and his pupils. * The head of the 

 spermatozoon, the male pronucleus in fertilization, may be de- 

 fined, in the case of the fishes at least, as "a salt of an organic 

 base and an organic acid, a protamin-nucleic acid compound." 

 The term protamin is used now to designate a group of closely 

 related proteins obtained from the spermatozoa of different 

 animals. The special protamin of each species is designated ac- 

 cording to the zoological name of that species; thus the protamin 

 of salmon is salmin, of herring (Clupea harengus), clupein, and so 

 on. The protamins are all strong bases; their aqueous solutions 

 give an alkaline reaction, and they unite readily with various 

 acids to form well-defined salts. They are protein bodies, giv- 

 ing the biuret reaction readily even without the addition of 

 alkali, and they are precipitated by most of the general precipitants 

 of proteins, such as the neutral salts, the alkaloidal reagents, etc. 

 Their solutions, however, are not coagulated by heat. The molecr 

 ular formula for salmin is given as C 30 H 57 N 17 O 6 . When decom-. 

 posed by the action of acids they yield simpler basic products, 

 the so-called hexon bases or diamino-bodies, and particularly the 

 base arginin (C 6 H 14 N 4 O 2 ), which is contained in the protamin of 



* For literature and details of the chemistry of spermatozoa, see Burian, 

 in "Ergebnisse der Physiologic," vol. iii., part i, 1904, and 1906, v., 832. 



