238 TRANSACTIONS OF THE CANADIAN INSTITUTR. [VoL. II 



which enters the animal body for assimilation does so in firm combina- 

 tion with complicated organic compounds, the elaboration of which occurs 

 only in the vegetable kingdom. Such compounds, he contends, when 

 absorbed and assimilated, yield haemoglobin. Kossel* has corroborated 

 Bunge's observations as to the occurrence of iron in the nucleins of yolk 

 and milk. 



Furthermore, Zaleski-f- found in the livers of various animals, washed 

 out and thoroughly freed from haemoglobin and inorganic iron salts, pro- 

 teids which contained iron more or less firmly combined. These were 

 albuminates of iron (Albuminat-verbindung des Eisens), and two, probably 

 three, nucleins containing iron (Nucleo-verbindungen des Eisens). The 

 latter vary in the power with which they hold the iron, and in one of the 

 nucleins which he calls liepatin the iron is so firmly combined that the 

 ordinary tests fail to show its presence, it being only detected in the asli^ 

 This hepatin differs from the haematogen of Bunge in that the latter 

 yields up its iron more readily and has a greater amount of the metal, 

 the haematogen containing 0'297o, the hepatin o-oii°/^. Zalesk , more- 

 over, determined that his iron-holding nucleins are present in the nuclei 

 of the hepatic cells. 



These nucleins have all the characters of the ordinary nucleins isolated 

 from pus, semen, etc., and as the latter are supposed to be present in, or to 

 form the substance known as chromatin to the cytologist, it is possible 

 that chromation usually if not always contains iron as firmly bound as in 

 the haematogen of Bunge and in the hepatin of Zaleski. It is true that 

 the analyses of nucleins, as given generally, do not point to the occurrence 

 of iron, but this can be explained by reference to the method employed 

 in their preparation. The nucleins, or rather chromatins, are soluble 

 in, and after a short time decomposed by, alkalies. Bunge has 

 shown that his haematogen loses its iron in solutions of potassic hydrate 

 after some days and contact with ammonic sulphide causes its decompo- 

 sition with the separation of sulphide of iron. In the preparation of 

 nucleins alkaline fluids have been used to dissolve the residue left by 

 digesting tissues, pus, etc., with pepsin and weak hydrochloric acid, or 

 with hydrochloric acid alone, and the alkaline fluid used contains the 

 nucleins (soluble variety) which one would expect, from the results of 

 Bunge's researches;!: to be free from iron (combined), if originally they con- 

 tained it. In this way we may explain why the nucleins from various 



*Weitere Beitrage zur Chemie des Zellkerns. Zeit. fiir Physiol. Chemie, Bd. X., p. 249. 

 tStudien iiber die Leber. I. Eisengehalt der Leber. Zeit. fiir Physiol. Chemie, Bd. X., pv)> 

 452-502. 



JSee on this subject specially the appendix. 



