266 
Negri hocUes 
peripheral granules were smaller and the yolk spherules stained blue. 
Sometimes it was possible to see around individual granules a certain 
amount of blue staining of karyoplasm, indicating in his opinion that 
the nucleoli were generating substances which were diffusing through 
the vesicular membrane to give rise to the yolk. Steinhaus (1890) in 
his study of the pancreatic cells, found the nuclei to possess safranin- 
staining nucleoli and on double staining with haematoxylin the nucleoli 
remained red, whilst the rest of the nucleus took on the reddish purple 
colour of haematoxylin. As the nucleolus lost its safranin-staining 
affinity, the cytoplasm acquired safranin granules. From this he 
inferred that the nucleolus of a pancreatic cell forms a substance 
prozymogen, which when it reacts unites with the elements in the 
cytoplasm to form, zymogen. Hertwig (1902, 1903) and his pupil 
Goldschmidt (1904 and 1905) in their researches on certain Protozoa 
have pointed out that in abnormal states of the cell melanin-like 
granules are found in the cytoplasm and are due to nuclear discharges. 
From our observations on the ganglion cells of the normal cat 
(PI. XI, fig. 12) we are able to confirm Luzzani’s work, and we regard 
the minute Negri-like bodies seen in this animal in the ganglion cells 
during normal health as due to a nucleolar discharge such as may occur 
normally in this animal. 
At the same time we may draw attention to the fact that in our 
sections of the normal brain of this animal, we saw minute blood 
elements (blood platelets) staining similarly to Negri bodies and 
situated in the blood vessels : this fact will always have to be reckoned 
with in describing minute Negri bodies in the blood stream. From the 
above studies, we see that the nucleolar matter in certain circumstances 
may be wholly extruded into cytoplasm or may undergo fragmentation 
and that these fragments then migrate into the cytoplasm whilst the 
nucleolus itself returns to its original form. The fate of these nucleolar 
particles when in the cytoplasm differs widely. In some cases they may 
totally disappear; in other cases, they become swollen up, fused and 
modified into intracytoplasmic accumulations, so-called yolk-iruclei, or 
again they may blend with the cytoplasm and give rise to cytoplasmic 
structures {e.g. Negri bodies). Further it has been shown that when 
these irucleolar spherules are first extruded into the cytoplasm, and 
while they are still situated in the immediate vicinity of the nucleus, 
they take on a stain approximating to that of nucleolar matter from 
which they were derived. The further they become removed from the 
nucleus the more do they tend to lose their original nucleolar staining 
