18'.l091.J AMPHIBIA BLOOD STIDIES. 237 



When the amount of chromatin has become so much reduced by division 

 and by degeneration of itself, then and not till then is reached the stage 

 of the fully formed corpuscle. Even in this stage there may be just so 

 much network chromatin left as to prompt a somewhat imperfect division 

 (Figs. 12-14), but these forms are extremely rare and the fully formed red 

 corpuscle is incapable of division henceforth, in other words, it has less 

 than the usual quantity of unmodified chromatin that an ordinary cell has. 

 It may be seen from this that Flemming's theory of the condensation 

 of the chromatin of hjematoblasts is not supported by the example 

 which he brought forward. The chromatin exists in the ha^matoblasts 

 from the first, there is no condensation of chromatin in the nuclei of red 

 cells, but there is, for the greater part of it, degeneration. 



Had Flemming, Pfitzner, and Strasburger studied fully the origin and 

 development of the haematoblasts they would, I believe, not have been 

 puzzled by the extraordinary abundance of the chromatin therein and 

 Flemming would hardly have striven to account for this abundance in 

 the way he did, either by derivation out of the cytoplasma, or by 

 expansion of originally condensed chromatin. 



From a study of my preparations there can be no doubt that the 

 eosinophilous substance of the haematoblasts is, on the one hand, derived 

 from the chromatin and on the other, transformed at the close of hjema- 

 toblastic life into haemoglobin. The transformation sometimes occurs 

 before this epoch for in the freshly shed blood of larval AinblysUnnata I 

 have seen mitotic haematoblasts in which a faint haemoglobin coloration 

 was present and in a few other, somewhat deeply pigmented cells the 

 addition of weak acetic acid solution dissolved out the haemoglobin and 

 showed mitotic figures. This was the rare exception of course. I do 

 not think tlie eosinophilous substance, although it also deserves to be 

 called haematogen, is the same as the interfilar or modified chromatin of 

 the fully formed red cells, for the latter does not react so definitely 

 towards eosin, and it does not as readily affect the haematoxylin in the 

 same way. As I have shown, they both, however, are derived from the 

 same source, and, apparently, the eosinophilous substance is farther on 

 the road to the formation of haemoglobin than the other. 



There are a number of facts which also support the view that haemo- 

 globin is derived from chromatin. Bunge* has extracted from the yolk 

 of hen's ^^^ and from milk, nucleins which contain iron very firmly bound 

 in the nuclein molecule. That found in the yolk Bunge especially 

 calls haematogen, because he believes that it is the antecedent of the 

 haemoglobin of the chick, and he puts forward the view that all the iron 



^Ueber die Assimilation des Eisens. Zeit. fiir Physiol. Chemie, Bd. IX., pp. 49-59. 



