Page 26 - Craventreatiseonpyorrh00crav

16 PYORRHCEA ALVEOLARI8. ambiguous as to the immediate derivation and eharacter of the calculus found in these pus cavities. The calculus of pyorrhoea alveolaris, whether in open or blind "pockets," possesses a composite character that at least it contains all the has escaped a proper emphasis hitherto ; elements of visible or salivary calculus, athough the extran- eous elements that usually are involved in oral tartar are here in modified proportion, in a ratio corresponding to difficulties of ingress; also, this hidden calculus possesses characteristics and elements that cannot be accounted for orally, being almost wholly of an organic derivation, a circumstance that contrib- utes to support of the sanguinary or serumal hypothesis. It is my belief that the source of these peculiar elements of the deeper "pocket" calculus is to be found inthe^pus^ itself ; that it should be called pygjnuLcalculus. The mass is thus composed of a combination of pyonal calculus and ordinary salivary calculus. The pus analysis from an average specimen, by Payne, in Quain's Dictionary of Medicine, shows that in 1,000 parts there are alkaline salts—other than sodium chloride—3.2, and of earthy phosphates and iron, 2.1. This gives a total of 5.3 in 1,000. Prof. Dalton's analysis of human saliva, parotid, as given in Litch's American System of Dentistry, reports in 1,000 parts that calcium phosphate is in 0.240 ; in a specimen from the submaxillary glands there were of 1 ,000 parts, calcium carbo- nate, calcium phosphate and magnesium phosphate, combined