EIGHTH ANNUAL REPORT. 119 



and in this paper is a preliminary study designed to outline the 

 subject. I have refrained in it from unnecessary details, stating 

 as briefly as possible only the lesions bearing directly on the dis- 

 ease. No constant or significant alterations have been found in 

 the general viscera, and for this reason they have not been in- 

 cluded in this study, though a complete examination was made in 

 each instance. 



No gross lesions of the central nervous tissues were found in 

 any case except one, where meningeal exudate was present, a 

 point confirmed by the microscopic examination. 



Since this study is intended only as a preliminary outline and 

 not as a finished article — most of the cases not having been care- 

 fully observed clinically — the pathological studies have been but 

 fragmentary. In the time at my disposal for the preparation of 

 this article it was manifestly impossible for me to carefully study 

 each of the cases, hence segments were selected from the cords, 

 with the full understanding that an examination of each seg- 

 ment, of each posterior root ganglion, and of many of the periph- 

 eral nerve fibers, as well as the entire encephalon, would be 

 necessary were the study designed to be a finished one ; such 

 minute examinations would seem wasted on material, most of 

 which has been casually observed by the keepers of the animals 

 and occasionally by the veterinarian. The observations are sub- 

 ject to the assumption that the general arrangement of the tracts 

 and fibers is the same in these animals as in man, an assumption 

 probably inaccurate. I am indebted for most of the gross patho- 

 logical observations to Dr. W. Reid Blair of the Park. 



Technic. — Previous experience in the study of the spinal cords 

 of the smaller animals has taught me that the removal of the 

 cord from its bony canal while the tissue was perfectly fresh fre- 

 quently resulted in formation of serious artefacts, consequently I 

 removed the entire spinal column in the first four of the following 

 cases, immersing it for 48 hours in a 5-per-cent. solution of forma- 

 lin, after which the bones were carefully cut away, exposing the 

 cord more immediately to the action of the formalin. Tissues for 

 general tissue changes were then transferred to graded alcohol, 

 embedded in paraffin, cut and mounted in the usual manner and 

 stained chiefly with hsematoxylon and eosin, also with Van 

 Gieson's picro-acid fuchsin. Sections stained with the Neisl blue 

 were also prepared in the same general manner. 



Segments intended for detection of degenerated fibers and 

 tracts, were hardened and prepared after the method of Marchii 

 or by the Busch modification of the same method. 



