found in the colon of a young man after death. 31 
“ with each other, like those in a hat, or in chamois leather; 
“ and the interstices between the fibres are filled up with 
“ earthy matter.” And at p. 34, he adds, “ in the centre of 
“ the concretion, a prune, or a cherry stone , or a small piece of 
“ bone, or a biliary calculus, is generally found.” 
Dr. Thomson states the average specific gravity of these 
concretions to be 1.4. The one I weighed was, as mentioned 
above, considerably heavier. This may be owing to one con- 
taining more of the fibrous substance than the other, or to 
Dr. Thomson not having employed an exhausted vessel to 
extricate the air from the pores of the calculus. Dr. Thom- 
son obtained from his analysis, albumen, common salts, 
phosphate of lime, phosphate of soda and the oat fibres, 
which he describes as “ undoubtedly of a peculiar nature, dif- 
“ fering from every animal and vegetable substance hitherto 
“ examined.” My results, in most respects, agree with Dr* 
Thomson's, except that I could not discover any albumen; 
and on the other hand, the calculi examined by him, do not 
appear to have contained either the ammoniaco-magnesian 
phosphate or gelatine. 
