PARALYSES IN DOGS 103 
fell into two stages, (1) a sudden improvement occurring in the 
first or second week, and (2) a slow improvement continuing for 
three or four months. 
Character of the clinical improvement 
The paralysis immediately following the operation was often 
a complete paraplegia, sometimes of one leg only, and rarely of the 
tail and sphincters. The dog lay in the kennel, seemingly stunned 
and not caring for food. He appeared feverish and _ thirsty. 
After a day or two, in spite of the paralysis, he made some attempt 
to get over the ground, with but partial success. The sudden 
improvement in the first or second week was often very marked, 
a paraplegia sometimes changing into a mere turning of one paw. 
Figs. 2, 3, 4 and 5 show characteristic changes in two of the dogs. 
Whether or not the improvement began suddenly, there was 
always a period of gradual recovery ending in a permanent state 
of residual paralysis. 
The question is, how much of the improvement is based on 
changes which are histologically demonstrable? The table (table 
1) indicates what the chief histological changes were (the topog- 
raphy of ten of the lesions is studied in Part 2). 
Histological summary 
In the early autopsies the location of the lesion was evidenced 
by a mass of débris, including broken down myelin in drops, 
leucocytes and round cells in clumps. A mass of granulation 
tissue had formed along the dura, at the place of injury. This 
entered the mass of débris. In this stage, cavities were not 
apparent, but in the neighboring grey matter were small areas 
of beginning necrosis. 
In animals autopsied at the end of one month, the most note- 
worthy thing was the appearance of cavity-like spaces. These 
were formed of connective tissue bands some of which had become 
well defined owing to the partial removal of the tissue débris. 
By this time the sear connected with the dura had become ‘quite 
dense. 
