THE CENTRAL NERVOUS SYSTEM 373 
from animals in whose history some suggestion of 
nervous system disease existed, Doctor Cadwalader could 
find abnormalities in only twenty-two cases, mostly how- 
ever of a very indefinite character. This observer 
further points out that in his experience with our 
material, his observations of our animals and a review of 
the literature, he is unable to find satisfactory instances 
of the so-called system or tract diseases such as tabes 
and lateral sclerosis. This he suggests is due to the 
absence of arterial sclerosis in the lower t3rpes of brain, 
intimating further that perhaps the relation of syphilis 
to human arteriosclerosis and degenerative nervous sys- 
tem disease is thereby strengthened. These facts being 
true it is not astonishing that massive cerebral apoplexy 
and cerebral softening do not occur(l). The lesions that 
have been found were either definitely infectious, as 
encephalitis or acute septicemia, tuberculosis, poliomye- 
litis, meningitis, or the minute hemorrhages and vague 
granularities or vacuolizations of nerve cells in toxemic 
conditions. The material being limited and broad state- 
ments being impossible, the important cases will be cited 
individually or in small groups. 
Convulsions. 
Before entering upon the special subjects, a word 
might be added concerning the clinical evidences of 
neurologic conditions as seen in the Garden. Perhaps the 
most common and certainly the most definite clinical sign 
of nervous disturbance is the convulsion. General spasms 
or fits are fairly common aniong the carnivores and 
monkeys, in the former most often associated with 
intestinal parasitism, in the latter with no especial 
relationship unless it be renal disease. The convulsions 
have been general, with and without the preservation of 
( 1 ) We have observed later, however, one case with very definite 
degenerative arterial disease; it will be discussd under the affections of 
the eye since the most definite and indeed only lasting sign of trouble was 
amblyopia, the attack being ushered in by a nondescript fit. 
