628 MR. youatt’s veterinary lectures. 
The plexus choroides are even more enlarged, and the fluid of a 
serous character was as abundant. I suspect that serous apo¬ 
plexy is no unfrequent disease in over-worked and half-starved 
horses ; but our post-mortem examinations have usually been too 
carelessly and superficially conducted : very rarely are they ex¬ 
tended beyond the few minutes that a trifling bribe will delay the 
departure of the knacker’s cart. We sadly need reformation 
here. 
Enlargement and Pressure of the Plexus Choroides not always 
injurious. —I perfectly recollect two cases during my attendance 
at the Veterinary College, and my yet more diligent attendance at 
the knacker’s yard—(the latter, gentlemen, is a place which I 
trust you will never frequent for the diabolical purpose of tor¬ 
turing a poor condemned and miserable animal, but where you 
may occasionally gain a clearer insight into the nature and pro¬ 
gress of disease than the lectures of the most talented instructor 
can afford you). There were two horses that had exhibited no 
apparent cerebral affection, yet in whom the plexus choroides 
were even larger than in the specimens before you. In one horse 
in particular they were as large as pullet’s eggs; but they were 
rather sarcomatous tumours attached to the plexus, than an 
actual agglutination and enlargement of that congeries of vessels. 
The larger portion lay on the corpora striata, and flattened them 
and left their impression upon them, but there was no collec¬ 
tion of fluid in the ventricle. 
Professor Podet relates a case in which the tumours com 
pletely occupied and filled the ventricles, and also pressed chiefly 
on the corpora striata, and produced a softening of the cerebral 
substance; there was not any nervous affection or impair¬ 
ment of intellect. The main pressure, however, in these cases, 
was on the anterior portion of the base of the brain ; and it would 
have been a point of interest to have ascertained whether the 
sense of smelling was affected. In effusion of fluid into the 
ventricles, the pressure is over the greater part of the base of the 
brain ; and, owing to the communication betw r een these cavities, 
reaches even to the medulla oblongata ; and hence, probably, the 
stupidity and loss of voluntary power which I have described. 
Determination of Blood to the Brain. —There has been some 
dispute among human pathologists as to the compressibility of 
the cerebral substance. It has been supposed accurately to fill 
the cranial box, so that there can never be any material variation 
in the quantity of blood in the brain. The incompressibility of 
the cerebral mass I may not be disposed to dispute ; but the 
perfect occupancy of the cranial cavity I am much inclined to 
doubt The elastic cellular substance about all the bloodves- 
