466 WALLACE LARKIN CHANDLER é 
Disturbance of respiration In moribund animals poisoned by nitro 
benzene, one almost invariably observes a disturbance of respiration, and 
in some instances a slowing of the pulse rate. Musser (1904) states tha 
cerebellar tumors often cause symptoms of this type. 
Headache and tenderness of the occiput.— Headache in animals is ve 
difficult, if not entirely impossible, to determine. However, certain action 
exhibited by animals poisoned by nitrobenzene might be interpreted t 
indicate headache; for instance, the animal’s desire to press its head agains 
some object. Dog I was observed to stand for long intervals with it 
head pressed against the attendant’s legs or against some solid objec 
(page 4381). And certainly the fact that the animal exhibited some dis 
comfort if the back of its head was touched, indicated a tenderness in th 
vicinity of the occiput. These symptoms have been observed in case 
of cerebellar tumors. 
Circus movements.— Rotation of the head and the neck was alway. 
observed in the case of birds poisoned by nitrobenzene. Thisisa character 
istic symptom observed in cerebellar pigeons. Rotation of the body about it 
longitudinal axis, observed especially in gray rats and sometimes in dogs 
is a symptom exhibited in cerebellar mammals. 
CAUSE OF THE LATENT PERIOD 
The fact that there often exists a long latent period, the period of tim 
elapsing between the administration of the drug and the onset of th 
symptoms, has led to much theorizing as to its cause. The following tw 
theories have been the most popular: the theory advanced by Ollivie 
and Bergeron and held to by Letheby, that nitrobenzene is converte 
into anilin in the body and that time is required for this transformation 
and the theory investigated first by Filehne and accepted by most recen 
writers, that the drug is so lightly soluble in the tissues of the body tha 
time is required for the absorption of it in sufficient amounts to produc 
the poisonous effects. 
Filehne has ably shown that the action of the drug does not depend on 
its conversion into other chemicals. Furthermore, he failed to find any 
trace of anilin in any of the organs of animals poisoned by nitrobenzene 
even by the hypochlorite test. His criticism of the isophenyleyanide test 
(used by Letheby) is justified, since in conducting this test nitrobenzene 
