148 
TUMOUR WITHIN THE CRANIUM. 
but the remainder possesses its natural appearance. The 
substance of the brain, as well as the spinal chord, is some- 
what deeper in colour than is usually seen. 
The fact of a tumour situated upon such an important 
organ as the brain, and there forming with little or no 
inconvenience to the animal to within a few days of its 
producing death, is to me, I confess, a mystery. 
[Cases similar to this recorded by Mr. Vincent are by no 
means uncommon, if we understand his description ; yet the 
existence of these accumulations upon the membranes of the 
brain, or within his ventricles, involves a highly interesting 
chemico-physiological inquiry. It would seem from the 
nature of the greater portion of them that they cannot be 
quickly formed, and it has occasionally been the case that they 
have attained to a very large size without causing any ob- 
servable symptoms. Lassaigne, in the Ann . Chem . et Phar . 
Ixii, 292, records an instance of this kind, in which he says the 
concretion weighed nearly fourteen drachms, w r as of the 
form of a hen’s egg, and existed in the right ventricle of an old 
horse ; and that no indications of its presence were manifested 
during the life of the animal. Its composition he found 
to be 
Cholesterine 58- 
Membrane and albuminous matter . . . 39‘5 
Sub-phosphate of lime . . . . - 25 
100 - 
Other instances are on record, in which the most violent 
symptoms have shown themselves prior to death. The pre- 
parations of two brains, thus diseased, are in the museum of 
the Royal Veterinary College, and we well remember the 
cases as related by Professor Spooner at one of the meetings 
of the Veterinary Medical Association. One of those speci- 
mens, in which a tumour exists in each of the lateral ven- 
tricles, involving the plexus choroides, w 7 as taken from a horse 
that he had examined only a fortnight before, apparently in 
health ; but phrenitis showed itself very early after purchase, 
and the animal died manifesting intense suffering. 
In the other, the tumour, w r hich is as large as an egg, is 
situated chiefly in one of the lateral ventricles, the septum 
lucidum being broken through, and a portion of the hippo- 
campus and the corpus striatum having disappeared. The 
horse had been driven to town in the morning, and on his re- 
turn was attacked w r ith the most violent symptoms resembling 
inflammation of the brain. When first seen by Mr. Spooner, 
