128 NEW YORK ZOOLOGICAL SOCIETY. 



tions. This consists in most instances of a finely granular breaking 

 down of the plaques without resulting chromatolysis, but in a few 

 cells this change is often present, when it is generally of a some- 

 what patchy character. A few cells show vacuoles, clearly a post- 

 mortem change. The cuticular membrane of the cells does not 

 stain, but appears sometimes finely granular and sometimes clear. 

 There is no apparent alteration in the ganglion cell nuclei or 

 nucleoli. 



Conclusions. — The lesions of this case may be summarized as 

 posterior sclerosis with disseminated patches of sclerosis and 

 chronic arteritis, chiefly confined to the posterior columns in the 

 lumbar and lower dorsal cord, resembling very closely the lesions 

 found in disseminated spinal sclerosis or the late lesions of tabes. 

 The alterations in the posterior root ganglia also simulate tabes 

 dorsalis. In some respects the changes may be said to strikingly 

 resemble those in human spinal syphilis. 



For the reasons mentioned in the text, it does not seem likelv 

 that the bacteria found in the sections bear any relation to the 

 lesions found. In so far as the sequence of lesions is concerned, 

 nothing is determined, unless we assume the vascular alterations 

 to be primary and the changes in the nerve tissues secondary to 

 them. 



GENERAL CONCLUSIONS. 



From these fragmentary observations it seems evident that 

 "cage paralysis" as noted by animal men is not a true disease 

 entity, but that it covers many types of paralysis, mostly of spinal 

 origin and probably as numerous as the like conditions in man. 



From the five cases outlined in this study it seems that the 

 lesions very closely resemble those of similar and well recognized 

 human diseases. It is therefore reasonable to expect that careful 

 study of the tissues of these animals, killed in the early stages of 

 the disease, may throw much light on the evolution of the same 

 class of disease in man. 



Concerning the causation of these spinal paralyses in wild ani- 

 mals in captivity, the present study determines nothing, except 

 that the causative factors, like the lesions, are probably variable : 

 but it has clearly shown that a more accurate clinical study of 

 these animals is necessary and must precede or accompany patho- 

 logical investigations. With the absolute control of every condi- 

 tion surrounding these animals (after their capture) in our power, 

 we should be able in the course of a few years to collect some 

 data of definite value in regard to the etiology of these diseases. 



