PHYSIOLOGICAL ACTION OF NITROBENZENE VAPOR ON ANIMALS 459 
nystagmus, of abnormal pupil reactions, nor that the animals had vomited. 
All the animals drank milk, and Dogs E and G ate some meat. 
On January 27, at 8 a. m., Dog F was found completely paralyzed 
except for slight movements of the hind legs, and there was a copious 
secretion of saliva. The knee-jerk reflex was good in both legs. At 
9.30 a. m.. this animal was howling excitedly. When disturbed it went 
into respiratory convulsions similar to those described for Dog VI (page 
437). The animal was killed at noon and its tissues were fixed according 
to the methods described earlier (page 429). 
Dog E refused food and water on this date, was wholly helpless, and 
howled incessantly. At 3 p. m., three hours after Dog F was killed, 
this animal was killed and its tissues were fixed in the manner 
described. 
Dog G took’ milk in the morning on this date, but refused it at night. 
It exhibited the running movements of the legs described for Dog X 
(page 440), and howled a good deal. 
On January 28 intense excitement was shown by Dog G. Its iegs were 
moving rapidly with the running movements already mentioned. These 
movements continued for long periods at a time, and then the leg and 
the abdominal muscles would stiffen in violent convulsions; the head 
thrashed about and the animal gave guttural sounds as if worrying a rat; 
finally the animal would grasp part of its bedding with its teeth and hold 
it firmly for a moment, during’ which time respiration would cease, and 
then, after a few gasps, the running movements would begin again. At 
times the animal shook its head vigorously, as if trying to get rid of 
something in its ear. This dog and the control, Dog H, were killed in 
the course of the morning and their tissues were fixed, as nearly as possible, 
after the same manner as were the tissues of Dogs E and F. 
Corresponding pieces of tissue from the different levels of the central 
nervous system of each of the four animals were carried thru the same 
fluids, and were finally stained and mounted on the same slide, as described 
on page 430. 
No histological changes could be observed in the cells of any part of 
the central nervous system, except in the Purkinje cells of the cerebellum. 
The changes in these cells were typically chromatolytic degenerations. 
