488 
Philippine Journal of Science 
1919 
tions as in the original primary stone. It is possible that with the 
decline of health, usually secondary to faulty metabolism and nu- 
trition, unfavorable fermentative changes may take place inside 
the bladder, which may subsequently give rise to the formation 
of a second layer of stone of distinct chemical composition, 
thereby making the primary calculus the nucleus of the second 
stone which Wells (25) considers a secondary calculus. Because 
of the injury produced by the resulting calculus, the condition may 
aggravate or the disease and general nutrition may improve as 
a result of treatment. In either case, a third layer of stone is 
formed with different chemical composition around the two- 
layered already existing calculus as a nucleus. This last layer 
may be considered as a third stone formation. Incidentally the 
analysis of several cases of multiple calculi removed (as in case 
25) show that the medullary layer — that is, the layer outside of 
the nucleus — of the larger one is chemically almost indentical 
with the nucleus of the two-layered smaller one and the cortices, 
or the outside layers, of both are similar, as indicated in fig. 1. 
It is apparent that the first stone 
formation (primary stone) of b 
took place simultaneously with 
the second layer of a and that 
the two-layered calculus of a 
acted as a nucleus of the third 
layer, thus playing the role of the primary stone of b. Conse- 
quently, for a given stone there are as many stone formations 
as there are layers, which may or may not be physically and 
chemically distinct from one another. 
From the fifty-eight cases examined there have been made 
out one hundred eighty-nine different layers or stone formations, 
the compositions of which are given in the following tables. In 
instances of multiple calculi the chemical composition of the 
largest stone is the only one considered. 
In the beriberi cases, Group I, thirty-six layers, 66.67 per cent, 
were chiefly phosphatic; and in those cases. Group II, having 
histories of poor nutritional condition fifty-nine layers, 72.88 
per cent, were phosphatic. In the group of well-nourished in- 
dividuals, Group III, seventy-six layers, there were 40.79 per cent 
of uric acid and urates, against 36.84 per cent of chiefly phos- 
phatic layers. In Group IV, where the nutritional condition 
was not noted in the clinical record, the incidence of phosphatic 
composition is alsoTiigher (nine layers or 50 per cent phosphate) 
against five layers or 27.77 per cent of uratic concretions. 
