IRON COMPOUNDS IN ANIMAL AND VEGETABLE CELLS. 211 
another condition which I regard as pathological. In the 
latter the nuclei were indistinct or disintegrated, their chro- 
matin had disappeared, and the surrounding connective tissue, 
with its blood-vessels and their red corpuscles even, gave in a 
few minutes, with warm ammonium hydrogen sulphide, an iron 
reaction, frequently so deep as to obscure largely the details, 
while the tissues, a little further away from such examples, and 
other ova under exactly the same conditions of treatment with 
the reagent, gave nosuch reaction. It may possibly be that the 
chromatin of such disintegrated ova furnished the iron observed 
thus diffused in the connective tissue and blood-vessels. 
In the nuclei of all the higher vegetable organisms the 
assimilated iron compounds are, on the whole, distributed as 
they are in the nuclei of the more highly developed animal 
forms, a fact which may be demonstrated in any Phanero- 
gamous plant, especially readily if its nuclei are large, as is 
the casein Erythronium americanum. In many of the 
preparations of the latter form the chromatin filaments were, 
in the process of teasing-out, partially or almost wholly set 
free from the nuclei containing them, and to the parts thus 
set free, as well as to the remainder, the glycerine and sulphide 
mixture always gave a distinct reaction for iron in a few days 
(fig. 17). Mitotic figures in such preparations appeared very 
sharply defined through the iron thus revealed in the chromatin 
elements. In successful preparations made by this method 
the reaction for iron is very marked, as much so as in those 
made with sulphuric acid alcohol; and in this respect there 
is a contrast between animal and vegetable nuclei, for in the 
former the glycerine and sulphide mixture brings out, after 
a longer application and less frequently, a reaction as intense 
as that which may be obtained after treatment of the nuclei 
with acid alcohol. 
Of nucleoli and nucleolar bodies there are at least three 
kinds. The reaction for iron given in one variety by the 
glycerine and sulphide mixture was weak, and it was obtained 
at the same time that it appeared in the chromatin network 
or filaments. These are smaller, apparently, in the hardened 
