208 A. B. MACALLUM. 
very small amount of iron present, there would appear to be 
distinctions which separate it from chromatin. My prepara- 
tions were chiefly obtained from the organs of the fasting 
animal, and as I did not succeed in my attempts at feeding 
artificially some examples of Necturus that I had, it is not 
possible for me to say whether the constitution of the nucleo- 
lar bodies is always similar to, or ever different from that 
described; but in preparations of the liver and other organs of 
specimens of Amblystoma punctatum killed soon after 
their capture, or after artificial feeding, the nucleolar bodies 
appeared to present the characters noted in the cells of the 
fasting animal, the smaller size of the elements in this case, 
however, not allowing as clear a view of them as was desired. 
In the nuclei of the liver-cells of Necturus, as illustrated 
in preparations made after the manner described, I frequently 
found a third element, whose significance is unknown to me. 
It manifested itself by the red stain which eosin gave it, the 
nucleolar bodies taking, in contrast, an ochre-red stain. It 
had no constant shape or form, in some cases being of a fila- 
mentous character, in others resembling a localised granular 
deposit (fig. 47) ; and when the structures were filamentous, 
several usually appeared in the same nucleus. The substance 
forming them did not contain the slightest trace of iron, and 
therefore appeared to have no relation to the nucleolar bodies 
or to the chromatin. I have not in any other organ observed 
similar structures. 
The disposition of the iron-holding compound in the nuclei 
of Amphibian ova deserves special mention. In the ovarian 
ova, whose nuclei contain no peripheral nucleoli, the iron is 
distributed as represented in fig. 36, the chromatin in this case 
forming a fine reticulum, in the trabecule of which large 
granules are found with lateral prolongations. The iron 
demonstrated in this preparation was set free by sulphuric 
acid alcohol, but a disposition of iron in the main like this may 
be found in similar nuclei when the latter are, on removal 
from the ova, broken into small pieces on the slide in the 
glycerine and sulphide mixture, and, thus prepared and provided 
