BIOCHEMISTRY OF THE SEXUAL ORGANS 293 



The investigation of the unripe spermatozoa of the salmon l 

 and of the mackerel 2 has shown indeed that instead of a pro- 

 tamine a histone is present, i.e. a substance which represents 

 the transition stage between the typical proteins and the 

 protamines. 



It would appear, therefore, that in the fishes the chemical 

 processes which lead to the formation of the spermatozoa consist 

 of a rearrangement of the constituents of the proteins of somatic 

 tissue, so that a gradual accumulation of the basic substances 

 rich in nitrogen takes place. This change leads at first to the 

 formation of histones, and in some species stops here. In the 

 majority of cases the change proceeds to the formation of sub- 

 stances belonging to the protamines. 



In the case of some Invertebrates (Arbacia pustulosa? 

 Sphcerechinus granularis*) the spermatozoa have been in- 

 vestigated and histones have been found to be present. 



Of the higher Vertebrates, the spermatozoa of the frog, 

 the cock, the boar, and the bull have been examined, 5 but 

 neither protamines nor histones were found. 



The acid substance isolated from the spermatozoa, the 

 nucleic acid, does not show any great variation in the different 

 species and classes of animals. It is, in fact, very similar to 

 the nucleic acid present in the nuclei of somatic cells, and is 

 probably identical with the nucleic acid prepared from the 

 thymus. These nucleic acids do not belong to the proteins, 

 but they exist in the cell always in combination with proteins 

 as nucleins or as nucleoproteins, according to the amount of 

 protein present in the combination. 



The nucleic acids are dry, pulverulent, white substances 

 of a decidedly acid character, containing 9 to 10 per cent, of 



1 Miescher, " Physiologisch-Chemische Untersuchungen iiber die Lachs- 

 milch," Histochemische Arbeiten, Archiv f. Experimentclle Pathologic u. 

 Pharmakologie, vol. xxxvii., 1896-1897. 



2 Bang (I.), "Studien iiber Histon," Zeitschrift f. physiolog. Chemie, 

 vol. xxvii., 1899. 



3 Mathews, " Zur Chemie der Spermatozoon," Zeitschrift f. phys. Chemie, 

 vol. xxiii., 1897. 



* Kossel, " Uber die einfachsten Eiweisskorper," Biochemisches Cen- 

 tralblatt, vol. v., 1906-7. 



8 Miescher, loc. cit., "Die Spermatozoon einiger Wirbelthiere," Histo- 

 chemische Arbeiten ; Mathews, loc. cit. 



