BIOCHEMISTRY OF THE SEXUAL ORGANS 313 



that it plays an active part in the synthetic functions of the nucleus 

 is even more suggestive. It was shown by Spitzer 1 that the 

 oxidising enzymes which are present in every cell are localised in 

 the iron-containing constituent of the nucleus, and Loeb concludes 

 that the nucleus must be regarded as the essential respiratory or 

 oxidising organ of the cell. 2 Oxidation processes are generally 

 supposed to be necessary only for the transformation of chemical 

 energy into heat and mechanical work. But they are, according to 

 Loeb, equally necessary for other more important and more general 

 vital processes, i.e. growth and cell division, which come to a stand- 

 still in the absence of oxygen. As a rule, cell division follows upon 

 the synthesis of nuclear material, especially chromatin material, 

 from the protoplasm of the cell. If we accept Schmiedeberg's 3 view 

 that in the living cell synthetic processes occur through the 

 intervention of oxygen, we may conclude that the oxygen which 

 is required for the process of cell division is needed for the 

 synthesis of nuclear material, and, since it is the iron-containing 

 organic compound present in the nucleus which lias the power of 

 bringing about oxidations, it would follow that the synthetic functions 

 of the nucleus (and hence cell division) are dependent upon this 

 compound. It must, however, be understood that these considera- 

 tions are still very hypothetical, and that other biologists 4 deny 

 that the nucleus is the respiratory or oxidising centre of the cell. 



Similar observations on the localisation of the intracellular 

 oxidising processes in the nucleus have been made by Lillie 5 and 

 by Unna. 6 



THE BIOCHEMISTRY OF FERTILISATION : ARTIFICIAL 

 1*A RTH EXOGEX ESIS 



What is the biochemical significance of the process of fertilisation ? 

 The answer to that question we owe mainly to the brilliant work of 

 Jacques Loeb " on artifical parthenogenesis. In 1899 he found, 8 as 

 the result of systematic attempts to induce development in the 



1 Spitzer, "Die Bedeutung gewisser Nukleoproteide fur die oxydative 

 Leistung der Zelle," PfliigeSs Arch., vol. Ixvii., 1897. 



- Loeb, Dynamics of Living If after, New York, 1906. 



3 Schmiedeberg, "Uber Oxydationen und Synthesen im Thierkorper," Archiv 

 f. e.i'penmentelle Pathologie v. Pkarmalcologie, vol. xiv., 1881. 



* See Verworn, Allgemeine Physiologic, 1909; also Pighini, "Uber die 

 Indophenyloxydase im Nervensystem," Biochem. Zeitsch., vol. xlii., 1912. 



5 Lillie (F.), "On the Oxidative Properties of the Cell Nucleus," Amer. Jour, 

 of Physio!., vol. vii., 1902. 



6 Unna and Golodetz, " Biocheuiie der Haut," in Oppenheinier's Hand-bitch 

 <ler Biochemie, Erganzungsband, Jena, Gustav Fischer, 1913. 



7 Loeb (Jacques), Artificial Parthenogenesis and Fertilisation, University of 

 Chicago Press, Chicago, 1913. 



8 Loeb (J.), "On the Artificial Production of Normal Larvae 'from the Un- 

 fertilised Eggs of the Sea-Urchin," Amei: Jour, of Physiol., vol. hi., 1900. 



