132 
MESSRS. J. 1^. LANGLEY AND H. M. FLETCHER 
In X. not only does the percentage of salts decrease with an increased rate of 
secretion of water, but the actual rate of secretion of salts decreases slightly. The 
latter is no doubt due to the stimulus being weaker in X. than in IX., owing to a 
partial elimination of the pilocarpin. In the other cases the rate of secretion of salts 
increases with the rate of secretion of water. 
The rate of secretion of organic substance is not much affected by the injection of 
dilute salt solution. This is clearest at the end of the experiment, when the salt 
solution is injected after bleeding. The injection, diminishing considerably the per¬ 
centage of organic substance in the saliva, diminishes somewhat the amount secreted 
in a given time, but not more than we should expect from the decrease in the strength 
of the stimulus. 
Tills, taken with what has been said above on the secretion of water and of salts, 
indicates that the secretion of organic substance depends udiolly, or almost 
wholly, up>‘^'^'^ strength of the stimulus, whilst the secretion of water and 
of salts depends also upon the amount of blood floiving through the gland. 
The same result, although less conspicuously, follows the first injection ; the percentage 
of organic substance in III. and IV. is much less than corresponds to the rate of 
secretion ; the amount of organic substance secreted in a given time is greater than in 
I. and II., since more pilocarpin was injected, and thus the stimulus stronger. 
