CHOROID PLEXUSES OF THE HORSE. 147 
Mr. H, E. Roscoe, of the Birkbeck Laboratory, at University 
College, has very kindly analysed the substance; and the follow¬ 
ing are the results obtained :— 
After the destruction of the organic matter by burning, a 
fixed inorganic residue remained, which was found to contain 
lime. The fat was removed by repeated washings with ether, 
and the remaining granules dissolved in hydrochloric acid, and 
lime and phosphoric acid were found to be present. 
There also appears to be some organic matter which is in¬ 
soluble in ether, and which is probably an organic acid. 
From the analysis, aided by what we have detected chemico- 
microscopically, we infer that the spherical bodies were com¬ 
posed of phosphate of lime; and the granular matter, which dis¬ 
solved with effervescence on the addition of the acids, consisted 
most probably of the carbonate of lime. 
Dr. Bennet, in his work on Cancerous and Cancroid Growths, 
has described similar bodies, which he detected in a cancroid 
tumour attached to the tentorium. He states that Mr. Nathaniel 
Ward, at a meeting of the Pathological Society of London, where 
the tumour was exhibited, remarked “ that the bodies under 
consideration appeared analogous to those described by Va¬ 
lentin, as occurring in the choroid plexus and pineal gland, and 
which, he states, appear under the microscope at first something 
likd air-bubbles, but on closer examination are found surrounded 
by a clear transparent membrane, so as to appear to be con¬ 
tained in a cell formation. On being pressed, they break in a 
radiated manner transversely or irregularly. After treatment 
with acids, the organic skeleton remains, and the concentric 
structure is still visible. They are with difficulty converted 
into an ash under the blow-pipe, and even then preserve their 
laminated arrangement. They are composed of carbonate of 
lime, with the baric phosphate mixed up with a little phosphate 
of magnesia and ammonia.” Dr. Bennet thinks that Gluge has 
also described similar bodies. 
Those I have examined differ from others described in not 
having an organic skeleton, but that they are identical, if not 
exactly similar, appears from the following statement of Dr. 
Bennet. “The true nature of these bodies is involved in some 
obscurity; but since writing the above observations, I have had 
several occasions of witnessing the mode of their formation in 
the choroid plexus. At first there seems to be deposited a 
quantity of mineral granules in round or oval patches more or 
less large. As these become more numerous, a clear centre, 
composed of transparent homogeneous mineral substance, may 
be seen in the centre, which gradually extends to the circum¬ 
ference, until the whole presents a uniform mass. The bodies 
