14 O l i S E R V A T I O N S ON THE
internal hydrocephalus," that all the ventricles were diftended; that, on
cutting into one of the lateral ventricles, ail the ventricles were emptied;
that, in thefe cafes, the paflages above dcfcribed were greatly enlarged
and that, in none of them, water was contained in the cavity of the fpinal
marrow, or between its pia and dura mater.
If cafes have occurred, fuch as Dr Haller quotes, in which both lateral
ventricles wci'e not emptied of water on opening one of them, the natural
communications mufl have been ihut, perhaps, by a degree of previous inflammation
and its confequenccs.
T. n.
IN the chronic fpecies of internal hydrocephalus, where the head is enlarged
by water within the ventricles, fome furgeons have propofed, and,
indeed, ventured to difcharge the water by a pun£ture with the trocar f .
But, in two or three cafes, where children had died from a great collection
of water within the ventricles, I have obferved, that, when the brain
coUapfed after cutting into one of the ventricles, fome part of the feptum
lucidum was lacerated by the weight of the brain, or of the water in the oppofite
vcntricle, which did not readily enough efcape by the natural communication.
So that, upon the whole, if we properly confider the various
dangers which muft arife from the puncture of the brain and the laceration
of the feptum between the ventricles ; from the unequal bending and preffure
of the parts when the brain coUapfes ; from the admiffion of the air to
the furface of the brain, which cannot well, or at all be prevented, becaufe
the bones cannot, by the application of a bandage, be brought to yield inwards,
fo as to be adapted exadlly to the fliape of the brain, fuch propofals
will appear improper in the higheft degree.
S E C T .
* See Tab. III. Fig. 4. 5.
t Mr L'Cai, Phil. Tran. vol. 47. Art. 40. p. 267.
N E R V O U S S Y S T E M .
T . in.
IF, indeed, the water is fituated between the dura mater and furface of
the brain, and of courfe between the fpinal marrow and its iheath from the
dura mater, a cafe which, I believe, occurs more rarely than is generally fuppofed;
or if, from a very evident fluftuation, chiefly about the bregma, we
ftrongly fufpe£l this to be the cafe, it will perhaps be advifcable to give the
patient the only, though fmall, chance of cure by operation.
In one cafe of a boy of three years of age, whom I vifited in 1764, along
with Dr Grant and the late Dr Whytt, the head was greatly enlarged, with
all the ordinary fymptoms of hydrocephalus. Dr Whytt, who had feen
feveral patients killed by a few ounces of water within the ventricles, and
had never feen the head fenfibly enlarged by water lodged in the ventricles
*, infifted that the water muft be iituated on the outfide of the brain;
and, as I could not prove what I fuppofed, that it was within the brain, it
was agreed that a furgeon ihould be called, and a punfture made. We
aiked Mr James Rae to attend, and I propofed that the pundture lliould be
cautioufly made, not with a trocar, but with a lancet, at the outer fide of
the bregma, as far as poflible- from the fuperior longitudinal fmus. The
Ikin being accordingly firll cut, and then the dura mater, and a probe introduced,
without difcharging water, we defifted from making any farther
attempt.
The puncture foon clofed, and the child furvived three months. After
death, I opened the head, in prefence of Dr Grant, and feveral other
gentlemen. We drew from the ventricles above two pounds of water;
and, on examining the communication between the lateral ventricles, it was
found
• See Dr Whytt's Works in 4to, p. 728. Note f.