BIOCHEMISTRY OF THE SEXUAL ORGANS 297 



The same quantitative relations have been shown to exist 

 in the spermatozoa of the herring, 1 and similar conditions may 

 be assumed to exist in the case of the spermatozoa of other 

 animals, the only difference being the nature of the protein 

 molecule which is combined with the nucleic acid. It is a 

 protamine or a histone in the case of the fishes, but a typical 

 protein in the case of the higher Vertebrates. 2 



Of the remaining 4 per cent, about one half consists of in- 

 organic salts, mainly calcium phosphate and calcium carbonate, 

 while the other half consists of an organic substance, the com- 

 position of which has not yet been recognised. The most 

 important fact known about it is that it contains 0'12 per 

 cent, iron in organic combination. The presence of iron can 

 be recognised only after incineration. To this iron-containing 

 organic substance Burrian 3 applies the name " Karyogen," a 

 word originally coined by Miescher to designate the residue which 

 he obtained after what Schmiedeberg's 4 calculations showed to 

 be an incomplete extraction of the protamine and nucleic acid 

 from the heads of the spermatozoa of the salmon. Since Macallum 5 

 was able to demonstrate by means of a microchemical method 

 the presence of iron in the chromatin of the nuclei of cells, it 

 seems possible that the " Karyogen " represents the chromatin 

 substance of the spermatozoon. 



The chemical analysis of the spermatozoon is therefore 

 complete. It shows that the tail is very rich in phosphorised 

 fats which are accompanied by cholesterin, fats, and a typical 

 protein. The head consists almost entirely (96 per cent.) of 

 a substance a nucleoprotein one component of which is 

 constant for the different species and classes the nucleic 



1 Bendix and Elstein, " liber den Pentosengehalt tierischer und mensch- 

 licher Organe," Zeitschriftf. allgem. Physiologic, vol. ii., 1902. 



2 Mathews, " Zur Chemie der Spermatozoen," Zeitschrift /. phys. Ckemie, 

 vol. xxiii., 1897. 



3 Burrian, Ergebnisse der Physiologif, vol. v., 1906. 



4 Miescher, " Physiologisch-chemische Untersuchungen iiber die Lachs- 

 milch, nach den hinterlassenen Aufzeichnungen u. Versuchsprotokollen des 

 Autors bearbeitet u. herausgegeben von O. Schmiedeberg," Arch. f. Experi- 

 mentelle Pathologic u. Pharmakologie, vol. xxxvii., 1896, and in Histochemische 

 u. Physiologische Arbeiten von Miescher. 



5 Macallum, " On the Demonstration of the Presence of Iron in Chromatin 

 by Microchemical Methods," Proc. Roy. Soc., vol. 1., 1892. 



