CAL 
CAL 
Genus T. | 
r 
Genus II. 
Genus III, 
f Species 1. Calculus of uric acid. 
.. g. urate of ammonia. 
.. 3 oxalate of lime. 
5 uric acid and earthy phosphates, in dis- 
I tinct layers. 
< uric acid and earthy phosphates, inti- 
•• ^ inately mixed. 
j urate of ammonia and phosphates, in 
u i distinct layers. 
3 urate of ammonia and phosphates, inti- 
•• mately mixed. 
I earthy phosphates, either mixed inti- 
1 mately or in fine layers. 
o J oxalate of lime and uric acid, in distinct 
L layers. 
S oxalate of lime and earthy phosphates, 
1 in distinct layers. 
^ , 5 uric acid, or urate of ammonia, earthy 
^ phosphates, and oxalate of lime. 
5 uric acid, urate of ammonia, earthy 
C phosphates, and silex. 
L 
s 
It becomes a question of great impor- 
tance and interest, to mankind how far the 
solution of calculi in the bladder may be 
practicable. From what has been said it is 
evident that being of very different chemi- 
cal composition the same solvent cannot be 
applicable to all of them. Long experience 
has sufficiently established the advantage of 
alkaline remedies ; and as the calculi com- 
posed of uric acid are questionably the 
most abundant, it is no doubt from the che- 
mical action they exert upon it that the be- 
nefit is derived. Lime, under the form of 
lime-water, has been employed as a solvent ; 
and from some experiments of Dr. Egan, it 
should seem that lime water acts with more 
energy than an alkaline solution of similar 
strength, in destroying the aggregation of 
urinai-y concretion. Mr. Murray bears his 
testimony to the same fact : “ I observed,” 
says he, “ this effect strikingly displayed in 
a compEU-ative trial which these experiments 
led me to make. In a dilute solution of 
pure potassa, a calculus of the uric acid 
kind was in part dissolved, the liquor, after 
a short time, giving a copious white preci- 
pitate with muriatic acid ; but the remain- 
ing calculus preserved its aggregation, ap- 
parently without much alteration, the exter- 
nal layer having been merely removed ; 
while a calculus of a similar kind, and dis- 
charged from the person, immersed in lime- 
water, became in a few days white and 
spongy : it appeared at length to be en- 
tirely penetrated ; its cohesion was sub- 
verted ; it presented a kind of loose scaly 
appearance, and the least touch made it fall 
down. The lime probably operates more 
upon the albumen or animal matter, which 
appears to serve as the cement or connect- 
ing substance, than upon the uric acid ; and 
in endeavouring to discover solvents for 
these concretions, our views ought perliaps 
rather to be directed to this operation than 
to the effect on the saline mattoi-. If lime 
when received into the stomach under the 
form of lime-water, can be secreted by the 
kidneys, as the alkalis unquestionably are, 
it would appear from these observations to 
be superior to them as a solvent.” 
CALCULUS denotes a method of com- 
putation, so called from the calculi, or coun- 
ters, anciently used for this purpose. 
Calculus specialis, or literalis. See 
Algebra. 
Calculus differenlialis is a method of 
differencing quantities, that is, of finding an 
infinitely small quantity, which being taken 
an infinite number of times, shall be equal 
to a given quantity. An infinitely small 
quantity, or infinitesimal, is a portion of a 
quantity less than any assignable one ; it is 
therefore accounted as nothing ; and hence 
two quantities only differing by an infinite- 
simal, are reputed equal. The word infi- 
nitesimal is merely respective, and implies 
a relation to another quantity ; for exam- 
ple, in astronomy, the diameter of the earth 
is an infinitesimal in respect of the distance 
of the fixed stars. Infinitesimals are like- 
wise called differentials, or differential quan- 
tities, when they are considered as the dif- 
ferences of two quantities. Sir Isaac New- 
ton calls them moments, considering them 
as momentary increments of quantities ; for 
instance, of a line generated by the flux of 
a point, of a surface by the flux of a line, 
or of a solid by the flux of a surface. The 
calculus differentialis, therefore, and the 
doctrine of fluxions, are the same thing, un- 
