ABNORMAL CONSTITUENTS. 25 



cannot contradict his assertion ; but as he also asserts that albumen 

 occurs in normal saliva, which is certainly not the case, at least in 

 any appreciable quantity, and as further, the recognition of small 

 qnantities of albumen is difficult and often impossible, for the 

 reasons given in the first volume, we are justified in doubting 

 whether albuminous saliva is of frequent occurrence. 



Biliary matters, and especially cholesterin, sometimes pass, 

 according to Wright, into the saliva. (See vol. i, p. 125.) 



Wright has described a large number of varieties of saliva, 

 classifying them according to the heterogeneous constituents which 

 they contain; thus he distinguishes ammoniacal saliva, saliva 

 containing hydrochloric acid, saline saliva, puriform saliva, 

 bloody saliva, fetid saliva, &c. In declining to adopt Wright's 

 results in our " Physiological Chemistry/' we by no means wish to 

 detract from the meritorious portion of his careful labours ; but 

 we do not think that the substrata on which such investigations 

 are founded are of a nature to rank high in exact sciences such as 

 chemistry and physiology. Descriptions of the subdivisions of 

 morbid saliva, as for instance, of bilious, bloody, puriform, 

 fetid, acrid, frothy, and gelatinous saliva, may have a certain 

 importance in relation to semeiotics, but cannot serve as substrata 

 for physiological inquiry. The illogical character of such a classi- 

 fication is obvious; the chemical investigations often do not justify 

 the conclusions which Wright has drawn from them; for sugar, bile, 

 lactic acid, &c. 5 are never recognised by him with such certainty as 

 chemists of the present day require ; moreover, recent physiology 

 might require further particulars regarding acrid, puriform, and 

 bloody saliva, while our present pathology pays less attention to 

 ontological ideas of disease than to investigations founded on actual 

 physical diagnosis and on morbid anatomy. We repeat that we 

 by no means wish to ignore the many interesting facts with which 

 science has been enriched by Wright's rich experience and inde- 

 fatigable labour. 



Although acid saliva has been observed in a large number of 

 instances, our knowledge of it is still very defective, for notwith- 

 standing the positive assertions of Wright, there is as yet no proof 

 that lactic acid is the cause of this acid reaction. Moreover, 

 Prout* has adduced no decisive proof of the presence of this acid. 



We have shown in the first volume, that the acid reaction of 

 the animal fluids may depend on the presence of other acids (as 

 for instance, several of the butyric acid group), or even of acid 

 * On the Diseases of the Stomach, 4th ed. p. 451. 



