20 
ABNORMAL FORMATIONS IN THE BRAIN. 
them I have measured and found to be about one-eighth of an inch 
in length and from one-sixteenth to one-twelfth in circumference. 
The membrane which invests them is white, dense, and fibrous in 
its physical characters ; its interior consists of a delicate network 
of the same kind of fibre, in which is deposited a quantity of very 
minute grains of what appears to be chalky matter ; and these 
grains are deposited in the delicate network in a manner very 
closely resembling the deposit of bone in the osseous tissue. 
These particulars I have fully satisfied myself respecting, by 
careful and repeated microscopic examination. 
I next placed a portion of the substance apart, and after it was 
carefully dried, I weighed half a drachm of the same, which I 
burned, and which left exactly eleven grains of earthy matter. The 
substance burned rapidly, with a large flame, emitting no per- 
ceptible odour. 
*** Mr. Haycock sent us a portion of the granular mass, as well 
as the residue of the incinerated portion ; and through the 
kindness of Dr. Babington we have obtained a correct analysis of 
them by Dr. Rees. Their composition Dr. R. has found to be 
“ membranous tissue cemented by fatty matters (principally 
cholesterine, and phosphate of lime. The earthy salt is in large 
proportion.” No carbonate of lime was found; “so that the earthy 
ingredient is not bony.” — E d. Vet. 
Remarks. 
For such deposits as the above described to exist in the 
brain (an organ so essential to the integrity of life in the higher 
animals), without giving rise to any symptoms to indicate their 
existence during life, appears very remarkable ; and can, I appre- 
hend, only be accounted for on the supposition that their develop- 
ment was very slow. To have suddenly appeared, would, I may 
assert, have given rise to such effects as in themselves would cer- 
tainly have been noticed; but, from the growth of these bodies 
being slow, those portions of brain in immediate contiguity with 
them would gradually accommodate themselves to the change, inde- 
pendent of any perceptible change in function. 
Similar morbid products are stated by Dr. Copland as being 
found occasionally in the lateral ventricles of the human brain, 
without any disease being suspected during life. Page 207, vol. i, 
of his Dictionary of Practical Medicine, he says, “ The choroid 
plexus, and the vascular plexus of the fourth ventricle, which are 
all productions of the pia mater, are often found remarkably dis- 
