PATHOLOGICAL APPEARANCES OF MYELITIS. 341 
about these so-called colloid bodies, but, so far as I am aware, 
their true nature has always been a matter of the gravest 
doubt, the current idea being that they result from a 
colloid transformation of previously existing protoplasm. 
This has always seemed a most indefinite and unscientific 
way of speaking of such matters, as the stages by which they 
arrived at this development have never been described, and 
why these, and none of the other tissues, should undergo 
colloid transformation has always remained unexplained. 
Wherever they occur, as in locomotor ataxia, the medullary 
sheaths of the nerve-tubes are generally distended, and their 
axis-cylinders are absent. This I have seen typically in 
several instances of the above-mentioned disease, similar 
lesions having also been described by many writers; and in 
an instance of syphilitic inflammation of the brain which I 
examined some time before making the above experiments, 
the appearances were so entirely similar that I beg to offer 
here a short account of them. ‘The patient had suffered 
from a chronic cerebral affection accompanied with great 
pain, and was one day suddenly seized with hemiplegia, and 
died shortly afterwards. He had a distinct chronic syphilitic 
history, and there was every reason to suppose that the cere- 
bral lesion was also dependent upon this diathesis. At the 
post-mortem examination every part of the brain was found 
comparatively healthy except the vessels at the base and a 
portion of the pes pedunculi on one side. In this latter 
situation was a dirty red softened mass with a small extra- 
vasation in the centre, extending through the middle of the 
pes pedunculi, and for some distance into the tegmentum. On 
hardening the entire nervous centres and examining them with 
the utmost care, it was found that at the situation of the lesion 
described the vessels were greatly distended and their coats 
covered with thick translucent exudation composed of round 
corpuscles. In the centre of the pes pedunculi were seen blood- 
extravasations and broken-down nervous tissue,but around this 
numerous large colloid bodies of an oval or rounded form were 
seen arranged in a linear manner according to the direction of 
the fibres. ‘They were very abundant, and,in many places, had 
undergone minute subdivision, the divided portions assuming 
a round and translucent aspect and constructing small depéts. 
Throughout the grey matter of the convolutions in many 
places, and in the region of the nucleus lentiformis on the left 
side, were scattered round transparent corpuscles distributed in 
an exactly similar manner to those seen in the grey substance of 
the spinal cord in many of the animals experimented upon. 
We may therefore conclude that this condition was a somewhat 
