242 A. B. MACALLUM. 
markedly affected by it, exhibiting an ochre-red colour so 
characteristic of the nucleoli in the hepatic cells of Necturus 
after similar treatment. Safranin leaves the nucleolus un- 
affected, but colours deeply the chromatin network and the 
iron-holding portions of the cytoplasm. When, however, the 
organism has been hardened in picric acid, the nucleolus 
exhibits no affinity for eosin, while it colours as deeply as the 
chromatin network does with hematoxylin and picro-carmine. 
From this it would appear as if the nucleolus were intermediate 
in composition between the nucleolus of higher animal cells 
and the chromatin of the nuclear reticulum. 
The occurrence of assimilated iron in the cytoplasm of 
Euglena viridis, if it is not chemically associated with the 
chlorophyll present, appears to indicate that the organism is 
closely related to the Protozoa, in common with which it has 
other characters.! If the view, that the assimilated iron in 
the cytoplasm of Protozoa is part of the antecedents of the 
zymogenic compounds of these organisms, is correct, it would 
explain the phenomenon in Euglena in which the presence of 
a short digestive “‘ tract”’ also postulates, to a certain extent, 
the occurrence of processes of nutrition belonging to the animal 
type. 
Fuugi.—The presence of nuclei has not yet been demon- 
strated in a large number of the Fungi, nor has the occurrence 
of a substance similar to the chromatin of other organisms 
been determined with any degree of certainty, except in a few 
forms ; and, therefore, the question of the occurrence and dis- 
tribution of assimilated compounds of iron in the cells of this 
class is not quite as easy of solution as that dealing with the 
1 G. Klebs, who has given special attention to the Euglenacee (‘“ Organiza- 
tion einiger Flagellaten-Gruppen und ihre Beziehungen zu Algen und Infu- 
sorien,” ‘ Untersuch. aus dem Bot. Inst. zu Tiibingen,’ 1881-85), is of the 
opinion that this group should be classed amongst the Protozoa. Khawkine 
(‘Recherches biologiques sur l’Astasia ocellata, ns., et ’Huglena 
viridis. Seconde Partie, L’Euglena viridis.’’ ‘Ann. des Sciences Nat., 
Zoologie,’ Serie 7, vol. i, 1886, p. 319) came to the conclusion, as a result 
of experiments, that Euglena takes in organic compounds in the dark, but 
in daylight assimilates only inorganic compounds. 
