468 WALLACE LARKIN CHANDLER 
doses, to affect these cells and produce the typical symptoms of poisoning, 
or even death, within a very short time after the administering of the 
poison. 
If the above assumptions are correct — and they can be so proved only 
after a long series of experiments dealing more exhaustively with the 
physics, chemistry, and physiology of the subject — then it is not sur- 
prising that, as was found, the latent period, as well as the intensity of 
the action of the drug, should vary in different individual animals, or 
even in the same individual at different periods of time; for neither the 
amount nor the kind of fats in the blood or the nervous tissues is abso- 
lutely constant. 
CONCLUSIONS 
The present work has confirmed the findings of previous investigators 
regarding all six of the points listed in the first paragraph following the 
review of the literature. In addition the following conclusions have been 
deduced: 
1. Aside from the possible disturbance of digestive functions and a 
possible asphyxia due to a direct action of nitrobenzene on the blood, 
most, if not all, of the observed symptoms of nitrobenzene poisoning may 
be explained on the basis of disturbances in the cerebellum or the cerebellar 
paths. 
2. Toxic doses of nitrobenzene, when administered by vapor inhalation, 
exert a direct action on the Purkinje cells in the cerebellum, causing 
chromatolytic degeneration of these cells. . 
3. Histological examinations have failed to reveal any definite changes 
in any of the organs of the body except the blood (presence of methemo- 
globin and morphological alterations of erythrocytes) and the cerebellum 
(chromatolytic degeneration of the Purkinje cells).! 
4. The size of the lethal dose probably depends on ecenditions such as 
the amount and the kind of fats in the blood, which favor or disfavor a 
concentration of the drug in the vicinity of the nerve cells. 
5. The latent period (the time elapsing between the administration of 
the poison and the onset of the symptoms) is undoubtedly due to the 
13 The writer does not mean to assert that histological changes do not occur in other tissues, especially 
in other parts of the central nervous system. Indeed, a further study of the present sections may yet 
reveal such changes. It would be strange if the action of nitrobenzene on the central nervous system were 
confined to a single type of cells only. Probably in cases of fatal poisoning other nerve cells are involved 
also, but it will be difficult to determine whether such changes are due to a direct action of the poison or 
are the result of a complication of changes attending death by poisoning. Further investigations are being 
made along this line. 
