THE CHEMISTRY OP THE NUCLEUS 203 



cell may recover. They represent exaggerated conditions of 

 normal processes, but where the latter stages show themselves, 

 regeneration of the cells becomes hopeless. 



As to the significance of this discharge of nuclear material, 

 I shall have a little to say after we have discussed the chemistry 

 of the nucleus. Professor Ewing and others will, I trust, 

 discuss the relationship of these modified nuclear discharges to 

 the intracellular appearances which by many have been regarded 

 as cancer and vaccine or variolous organisms. 



5. The Chemistry op Nuclear and Cytoplasmic Matter 

 respectively 



Here, in studying the chemical composition of the two com- 

 ponents of the cell, we meet with certain remarkable facts, for 

 not a few of which we are indebted to Professor Macallum. 

 There are certain substances of great chemical activity bound 

 up in the nuclei which are present to but slight extent, if, indeed, 

 at times they can be recognized in the cell body. Notably is 

 this the case with phosphorus (Lilienfeld and Monti, Macallum), 

 as also with " masked " iron — iron, that is, in fairly firm com- 

 bination, so that it is only loosened and made to respond to the 

 tests for free iron after having been subjected to preliminary 

 dissociative treatment. On the other hand, certain substances 

 found to be present in the cell body are absent from nuclear 

 matter. Among these, as Macallum has pointed out, are potas- 

 sium and chlorides. When now we come to study the proteid 

 contents of the nuclei, we find that these, unlike ordinary proteins 

 of the cell body, are undigested by gastric juice, and that the 

 undigested material consists of the nuclear network and its 

 chromatin and the nucleoli. We owe especially to Kossel's 

 investigations the explanation of these peculiar features. Cell 

 nuclei, that is, contain as a main constituent a special group of 

 proteins — the nucleoproteins. These nucleoproteins split up into 

 albumen (histon) and nucleins, and it is these nucleins in par- 

 ticular that resist the action of gastric juice, and further, are 

 characterized by high phosphorus content. These, like the 

 nucleoproteins, are of a proteid nature ; upon further decom- 

 position they yield albumen and nucleic or nucleinic acid, and 

 . can be further broken down into the xanthin bases or purin 



