IRON COMPOUNDS IN ANIMAL AND VEGETABLE CELLS. 227 
substance is allied to nuclein, and, according to Gourlay, the 
nucleo-albumin which he isolated from the thyroid was derived 
in large measure from the colloid matter which he, relying on 
the reaction of Lilienfeld and Monti, found to contain phos- 
phorus. If colloid matter is therefore a nucleo-albumin, its 
freedom from iron renders it, in contrast with the chromatins, 
a subject of special interest. 
Assimilated iron is rarely found in the cytoplasm of the cells 
of the higher vegetable organisms, and amongst the examples 
illustrating its presence may be mentioned the cells of the 
nucellus in the ovules of Erythronium americanum, and 
those of the gluten layer in the wheat-grain. The cytoplasm of 
the cells of the nucellus, when fertilisation has taken place, and 
even before this occurs, gives, after treatment with sulphuric 
acid alcohol, a distinct reaction for iron, which, however, in 
respect to intensity, is not to be compared with that mani- 
fested in the nuclei of the same cells. The iron in the cyto- 
plasm in this case is not due to diffusion from the nuclei during 
the course of treatment with the liberating reagent, for it is 
also demonstrated in this situation in the glycerine and sul- 
phide preparations. As the nuclei of the nucellus are much 
richer in assimilated iron than those of other parts of the 
ovule, except the embryo sac, it is possible that the cyto- 
plasmic iron compound is intra vitam diffused from the 
nuclei, and, further, as the cytoplasm of the embryo-sac of this 
stage sometimes gives a diffuse reaction for iron after it has 
been treated with acid alcohols, its presence here may be due 
to a similar diffusion from the cells of the nucellus. I have 
observed in certain preparations in which the nuclei of the 
embryo-sac were in the stage of division, a large number of 
iron-containing granules interspersed amongst the fibrils of the 
achromatic spindles, and as in other preparations similar 
granules were stained with hematoxylin, hke the chromatin 
loops, it would appear as if the granules were formed of chro- 
matin. The cytoplasm holding these granules gave no reaction 
for iron. 
The cytoplasm of the cells of the gluten, or so-called aleu- 
