496 TRANSACTIONS OF THE CANADIAN INSTITUTE, [VoL. VI. 
of the vacuoles, and in the cytoplasm generally (Figs. 42-49). The 
reaction is usually intense in the corpuscles, so much so that they may 
appear not dark green but black from the excess of ferrous sulphide 
developed in them by the reagent. The reaction in the cytoplasm is 
much less marked but distinct. lt may be diffuse, but if the prepara- 
tion, though successful, has been only a few days in the reagent, one 
may observe, in a majority of the cells, that the reaction is limited to 
the cytoplasmic network (Figs. 50 and 51). In some cells a series of 
granules constituting a membrane about the corpuscles like those 
already described, gives a very distinct reaction (Fig. 46). Sometimes 
the number and size of the corpuscles thus demonstrated suggest the 
character of granules, but there is, in the majority of such cases, one 
at least which is of the usual size (Figs. 45, 46, 47, and 49). The 
reaction in the wall of the vacuole may be very distinct, and especially 
in granules located in it. (Figs. 42, 43, 44, and 48). 
On applying the method to demonstrate the presence of organic 
phosphorus, the later is found to be localized in the same manner as 
the organic iron. The corpuscle is rich in it, and the wall of the 
vacuole in contact with the corpuscle gives a distinct reaction for it, and 
at times specially in the granules found in it. Portions of the cyto- 
plasm, which appear to correspond to the nodal points of the reticulum, 
give a deep reaction (Fig. 56). 
It is evident from the presence of “masked” iron and organic phos- 
phorus, both distributed in the yeast cell to an extent parallel with the 
distribution of the substance which stains with hematoxylin, that the 
organism contains in its corpuscle or corpuscles, in its cytoplasm, as 
sometimes in the wall of its vacuole, a substance closely related to the 
chromatin of higher organisms, but differing from the latter in the effect 
exercised on it by artificial gastric juice. The stainable substance found 
in the corpuscles further differs from ordinary chromatin in that it has 
no affinity for acetic-methyl green. 
There remain now to be described structures which are, so far as my 
observations go, to be found only in S. Lwdwzgzz, when cultivated in the 
sap of the iron-wood tree. The character of these structures is seen by 
an examination of Figs. 21-27, and 29, in which they are illustrated. 
They are not all of the same type. As in Figs. 21 and 29 one may 
observe a large nucleus-like body in which a network, somewhat like that 
found in a fully typical nucleus, exists. There may also be a corpuscle 
in this structure which simulates a nucleus. In some cases the structure 
in question may resemble a nucleus in the stage preparatory to the for- 
ee em 
