1894.) Chemico-Physiological Discoveries: The Cell. 109 
for example, does not dissolve or even swell up in 10 per cent. 
salt solution, hence it is not a globulin or simple proteid ; fur- 
ther, it does not disappear on treatment with hydrochloric 
acid of moderate strength, as nuclein does. Again, plastin is 
much more difficultly soluble in alkalies than nuclein. Now 
as a matter of fact these two bodies have an extremely close 
relationship; they are both nucleins, having the same general 
type of structure; they differ merely in the proportion of 
nucleic acid and proteid. The plastin of the histologist, 
therefore, is simply a form of nuclein, less acid in character 
because it contains less nucleic acid and a larger proportion of 
proteid; hence, it likewise contains less phosphorus and for 
the same reason is more insoluble in alkalies. 
In a general way we may say that the so-called nuclear sap 
or nuclear matrix is composed practically of a globulin-like 
body, just such as is found in the cytoplasm and which by 
digestion with artificial gastric juice is converted into soluble 
products, as proteose and peptone. The bulk of the nucleus, 
however, is composed of material insoluble in gastric juice. 
The bodies composing this indigestible matter are all phos- 
phorized; in fact, they are nucleins of various kinds. Thus, 
the so-called chromatin network which is distinguishable from 
all other constituents of the cell by its strong affinity for 
various dyes is composed of a nuclein rich in phosphorus, 
viz.: a nuclein with a large content of nucleic acid and a cor- 
responding smaller content of proteid. The nucleoli, on the 
other hand, which have a less pronounced affinity for dyes 
than the chromatin, are composed mainly of the so-called 
plastin, i. e. a nuclein comparatively poor in phosphorus and 
not readily soluble in alkalies. In other words, and this I 
think is the point deserving of special emphasis, the cell nu- 
cleus in all cells is composed mainly of nucleins, compound 
bodies made up of proteid matter and nucleic acid, the latter 
rich in phosphorus, the individual parts of the nucleus vary- 
ing somewhat in accord with the varying character of the 
nucleins as determined by the proportions of proteid to 
nucleic acid. That is to say, “in the processes of vital activtiy 
there are changing relations between the phosphorized con- 
