H. W. Acton and W. F. Harvey 
257 
account Prowazek has given these parasites the name Chlamydozoa. 
With further multiplication of the ‘ elementary granules ’ the ‘ cell- 
inclusion ’ breaks up leaving only debris, and the whole cell becomes 
completely filled by the ‘elementary granules.’ Hartmann and Leber 
observed dumb-bell-shaped division forms among ‘the elementary 
granules.’ ” 
With this general statement we ma}'^ now proceed to our own 
observations on Negri bodies. 
To test the specificity of Negri bodies, we carried out a number of 
experiments on normal guinea-pigs with the following substances :— 
(i) Russell’s viper venom. 
(ii) Cobra vemon. 
(iii) Tetanus toxin. 
(iv) liiving Bacillus pyocyaneus emulsion. 
(v) Brain matter of a healthy dog which had been preserved 
in glycerine for 72 hours. 
(i) Some 20 experiments are carried out with Russell’s viper 
venom. 
In two of them out of the 20 we were able to find bodies varying from 
1 to 6 /u. in size in the cells of the fascia dentata although not in the 
ganglionic layer of the Ammon horn. Some of these bodies were 
identical as regards their staining reaction, situation and character 
with those of the Negri bodies, as found in this animal, whilst others 
did not give these reactions and were probably cytoplasmic in origin 
(PL XI, fig. 1). The Negri-like bodies were very few in number and 
required a good deal of searching for, but in the Purkinje cells of one of 
these guinea-pigs they were fairly large and numerous. 
In these experiments doses of O'OOl to 0'0005 milligrammes per 500 
grammes weight of guinea-pig were injected subcutaneously in the 
region of the upper abdomen. Both the guinea-pigs showing these 
bodies survived for over 48 hours; most of the others died earlier. 
(ii) Cobra venom-. 20 experiments were performed on guinea-pigs, 
the minimal lethal dose being found to be O'OOOl gramme per 500 
grammes of guinea-pig weight. Sections were examined from the 
hippocampus major and cerebellum of all these animals, but no Negri 
bodies were seen. In some of the large ganglion cells ovoid masses of 
cytoplasmic material were observed, which did not stain with Mann’s 
method and were probably of the nature of the plastids. 
17—2 
