XIV, 5 
Padua: Cystolithiasis with Dietetic Deficiency 487 
Calculus analysis {one dull whitish stone). 
Grams. 
Whofe stone 
5.5 
Portion analyzed 
2.0 
Cortex analyzed 
0.9 
Medullary layer analyzed 
0.8 
Nucleus analyzed 
0.3 
Weight by proportion. 
Grams. 
Whole cortex 
2.5 
Whole medullary layer 
2.2 
Whole nucleus 
0.8 
Composition of layers. 
Layer. 
Constituent. 
Chief. 
Minor. 
Amorphous phosphate and cal- 
cium carbonate. 
Calcium oxalate and trace of 
ammonium urate. 
Amorphous phosphate, cal- 
cium oxalate, and ammo- 
nium urate. 
Calcium oxalate, ammonium 
urate, and amorphous phos- 
phate. 
The analysis of each layer of an individual calculus is given 
as each may be regarded as a distinct stone formation. It 
should be recalled that a stone is formed, in the presence of a 
binding substance, around a nucleus, which may be a mass re- 
sulting from an inflammatory process of the vesical mucosa (pus, 
blood, or bits of necrotic tissue) , or foreign bodies such as frag- 
ments of bougies, pins, silk sutures, or a previously formed stone 
which may have come from the kidney, or one that has been 
formed earlier in the bladder around which other layers of stone 
are formed vdth the same or different chemical composition. 
The disposition of the bladder calculus in layers of different 
chemical substances may be the result of a change in the com- 
position of urine secondary to a modified general metabolic pro- 
cess. Sondern,(22) in speaking of the increase of the calculus 
in size, says that — 
The abnormal condition during which the nucleus is found may be tem- 
porary and that the stone can continue to grow in size even if normal 
urine is excreted. 
Once the nucleus of stone is formed around a mass of “foreign 
body” coated by the binding substance or albuminoid framework, 
the tendency is toward a more or less continuous deposit of prac- 
tically the same chemical substances in almost the same proper- 
