CHEMICAL RELATIONS OF NUCLEUS AND CYTOPLASM 247 



admit of a safe generalization. They are, however, enough to indi- 

 cate the probabihty that chromatin may pass through a certain cycle 

 in the life of the cell, the percentage of albumin increasing during 

 the vegetative activity of the nucleus, decreasing in its reproductive 

 phase. In other words, a combination of albumin with nuclein or 

 nucleic acid is an accompaniment of constructive metabolism. As 

 the cell prepares for division, the combination is dissolved and the 

 nuclein-radicle or nucleic acid is handed on by division to the daugh- 

 ter-cells. It is a tempting hypothesis, suggested to me by Mr. A. P. 

 Mathews on the basis of Kossel's work, that the nuclein is in a chem- 

 ical sense the formative centre of the cell, attracting to it the food- 

 matters, entering into loose combination with them, and giving them 

 off to the cytoplasm in an elaborated form. Could this be estab- 

 Hshed, we should have a clue to the nuclear control of the cell 

 through the process of synthetic metabolism. Claude Bernard 

 advanced a nearly similar hypothesis two score years ago ('78), main- 

 taining that the cytoplasm is the seat of destructive metabolism, the 

 nucleus the organ of constructive metabolism and organic synthesis, 

 and insisting that the role of the nucleus in nutrition gives the key 

 to its significance as the organ of development, regeneration, and 

 inheritance.^ 



That the nucleus is especially concerned in synthetic metabolism 

 is now becoming more and more clearly recognized by physiological 

 chemists. Kossel concludes that the formation of new organic matter 

 is dependent on the nucleus,^ and that nuclein in some manner plays 

 a leading role in this process ; and he makes some interesting sugges- 

 tions regarding the synthesis of complex organic matters in the living 

 cell with nuclein as a starting-point. Chittenden, too, in a review of 

 recent chemico-physiological discoveries regarding the cell, concludes : 

 "The cell-nucleus may be looked upon as in some manner standing in 

 close relation to those processes which have to do with the formation 

 of organic substances. Whatever other functions it may possess, it 

 evidently, through the inherent qualities of the bodies entering into 

 its composition, has a controlling power over the metabolic processes 

 in the cell, modifying and regulating the nutritional changes" ('94). 



1 " II s^mble done que la cellule qui a perdu son noyau soit sterilisee au point de vue de 

 la generation, c'est a dire de la synthese niorphologique, et qu'elle le soit aussi au point de 

 vue de la synthese chiniique, car elle cesse de produire des principes immediats, et ne peut 

 guere qu'oxydtr et detruire ceux cjui s'y etaient accumules par une elaboration anterieure du 

 noyau. II semble done que le noyau soit \e germe de nutrition de la cellule; il attu'e autour 

 de lui et elabore les materiaux nutritifs " ('78, p. 523). 



■■^ Schiefferdecker und Kossel, Gewebelekre, p. 57. 



