1899-1900.] Dr W. G. Aitchison Eobertson on the Saliva. 155 
Note on the Activity of the Saliva in Diseased Conditions 
of the Body. By W. G. Aitchison Robertson, M.D., 
D.Sc., F.R.C.P.E. 
(Read February 19, 1900.) 
The investigation was undertaken to find out in what way the 
activity of the salivary ferment varied in different diseased con- 
ditions of the body. 
In order to eliminate the fallacy which might arise from the 
hourly variation in the diastatic power of the secretion, the experi- 
ments were always performed at the same hour each evening. 
Each individual was made to wash his mouth out thoroughly with 
slightly warm water, and, during the succeeding half hour, all the 
saliva which he secreted was received into a vessel and measured. 
Two cubic centimetres of the saliva were then mixed with ten cubic 
centimetres of starch mucilage at the temperature of 38° C., and 
the mixture was then kept at this temperature for ten minutes. 
At the end of this period the condition of the starch present was 
noted, and further action of the ferment was prevented by rapidly 
boiling the mixture. The amount of sugar which had been formed 
by the ptyalin was then estimated by titration against standard 
Fehling’s solution. 
Above one hundred cases of disease of various kinds were 
investigated, in order to see if the activity of the salivary ferment 
had undergone any change. 
G astro-intestinal Disorders. — Twenty-one cases were examined. 
The average amount of sugar formed in these was 0*089 gramme 
(the normal average being taken as 0*080). In chronic gastric 
catarrh this figure varied from 0*078 to 0*1 gramme. In acid 
dyspepsia the amount of sugar formed is above the healthy average, 
while in ulceration of the stomach, the amount is generally only 
slightly below the normal average. In dilatation of the stomach, 
the salivary ferment was found to be almost absent, or at least 
inactive. In cirrhosis of the liver the amount of sugar is not 
reduced, and in some cases it is greatly increased. 
Pulmonary Diseases . — In these diseases generally the salivary 
