1888-89.] Mr Irvine & Dr Woodhead on Carbonate of Lime. 337 
carbonates, often has only a very slight reaction* on turmeric 
paper, while clear urine is usually rich in alkaline carbonates.” 
Hence it is easy to see why urinary calculi consisting of carbonate 
of lime are of very common occurrence in herbivorous animals. 
Carbonate of lime also sometimes occurs in human urine with an 
alkaline reaction, and indeed sometimes, though very rarely, we meet 
with urinary calculi in the human subject consisting for the most part 
of carbonate of lime. Prout was the first who made this observation, 
but similar calculi have been since found by Cooper, Prout, Smith, 
Gobet, and Fromhery. Lehmann also points out that in animal 
concretions considerable quantities of carbonate of lime may be 
deposited with the phosphate. Thus he mentions nasal concretions 
containing 21 *7 per cent, carbonate and 46 *7 phosphate of lime; 
phlebolich 8 ’3 per cent, to 24 - 3 per cent, carbonate, and 50T4 per 
cent, to 69*7 per cent, of phosphate of lime. In the concretion 
from the heart of a man with hydrothorax 23 per cent, of carbonate 
and 50 per cent, of phosphate of lime. In a concretion taken from 
a stag’s heart 66*7 per cent, of carbonate and 25 per cent, of 
phosphate of lime. Some stony concretions from the peritoneum 
of a man were found to contain 34 per cent, of carbonate and only 
19*32 per cent, of phosphate of lime. Lassaigne found 83*36 
per cent, of carbonate of lime in a salivary concretion from a 
horse. 
§ 5. The next factor to be considered is the mass of active cellular 
elements with which the blood and lymph are constantly coming in 
contact. These fluids must be looked upon as the carrier from 
which the cells obtain their nutrient material and also the vehicle 
for carrying off effete matter. In the immediate neighbourhood of 
these cells most marked changes take place in the composition of 
the fluids in which they are bathed. One of these changes is, that 
there is always an increase in the amount of carbonic acid in 
this position, and there is, as we have indicated, frequently, but by 
no means invariably, a deposition of phosphate of lime with a small 
quantity of carbonate. If the salts are removed at once they may 
remain as such, but if they are again acted upon by the phosphoric 
acid and the alkaline phosphates the lime salts are redissolved and 
we have a return to the normal condition. Let us see how this 
bears on the process of calcification of bone. In the first place, 
VOL. xvi. 30/8/89 Y 
