H. W. Acton and W. F. Harvey 271 
Figs. 5 and 6. Rabbit, (5) Purkinje cell; (6) ganglion cell of hippocampus major- 
(a) Nucleolus and fragmented particles; (6) minute Negri bodies. 
Fig. 7. Guinea-pig; cell from the fascia dentata. (a) fragmented nucleolus; (b) cap 
shaped Negri body. 
Fig. 8. Guinea-pig Purkinje cell from cerebellum, (a) fragmented nucleolus; (6) large 
Negri body; (c) small Negri body; {d) neuroglial cells. 
Fig. 9. Guinea-pig, ganglion cell of the hippocampus major, (a) irregularly shaped 
nucleolus; (6) nucleolar particle just being extruded; (c) large Negri body; (d) cap 
shaped Negri body; (e) neuroglial cell. 
Figs. 10 and 11. Dog. Hippocampal ganglion cells. (Iron haematoxylin and Van 
Gieson.) (a) Extruded nucleolus stained green and vacuolated; (a') green stained 
nucleolus; (6) Negri bodies; (c) neuroglial cell. 
Fig. 12. Normal cat, ganglion cell of hippocampus major, (a) Nucleolus; (&) minute 
structure resembling a Negri body. 
Figs. 13 and 14. Negri bodies of the dog. (Stained iron haematoxylin and Bordeaux 
red.) (a) Nucleolus; (&) small dark staining Negri bodies; (6') large older Negri 
body (pink), showing the hasophile granules of Volpino. 
NOTE ON THE FOREGOING PAPER. 
Id the progress of our knowledge of the so-called Chlaraydozoa, 
there have been four stages. 
1. In the case of certain diseases, such as vaccinia and variola, 
scarlet fever, hydrophobia, trachoma, measles (?), foot-and-mouth 
disease (?), etc., inclusions have been found in epiblastic cells, epidermis 
or ganglion cells. These cell-inclusions have received names according 
to their discoverers, such as Guarnieri’s bodies, Mallory’s bodies, Negri’s 
bodies, Prowazek’s bodies, etc. 
2. A certain number of investigators have taken the view that 
these cell-inclusions are the actual parasites; they have therefore given 
them generic and specific names such as Cytoryctes vacciniae and 
variolae, Gyclasterium, Neuroryctes hydrojjhohiae, etc. They have 
further described a supposed “life-cycle” for them, and have attempted 
to classify them in one or another group of the Protozoa. 
3. Other investigators have come to the conclusion that these cell- 
inclusions are not parasites at all, and their life-cycles are purely 
illusory; they have shown that the cell-inclusions are degeneration- 
products of the cell-nucleus, consisting of extruded nucleolar substance. 
4. Finally Prowazek, Hartmann and others have tried to prove 
that in these diseases true parasitic organisms are present in the form 
of very minute bodies which divide in a peculiar manner and are quite 
Parasitology rv 
