122 
MESSRS. J. X. LANGLEY AND H. Isl. FLETCHER 
It will be seen in the above experiment that, notwithstanding the very slow rate of 
secretion of the sympathetic saliva, it contains a higher percentage of salts than five 
out of the six other samples of saliva collected. Comparing it with sample IV. wm 
see that, whilst it was secreted at one-tenth the rate, it contains '1 per cent, more salts. 
In the other samples of saliva, with the exception of VI., the salts follow Heiden- 
hain’s law. The exception we shall have occasion to refer to later (p. 148). 
A still more striking instance of the high percentage of salts which may be present 
in sympathetic saliva, compared with that proj^er to its rate of secretion, is given in 
another experiment made by us, the details of which have been already published.* 
From this we take the following ;— 
Table VI. 
Saliva obtained by— 
Rate of secretion 
per minute in c.c. 
Percentage of salts. 
Stimulating left chorda before atropin given 
4-13 
•742 
Stimulating left chorda and sympathetic 
•073 
after 15 mgrm. atropin 
•619 
Stimulating right chorda before atropin given 
4-200 
•766 
Stimulating right sympathetic after l5 mgrm. 
•705 
atropin 
•023 
Here, on the right side, the rate of secretion of the chorda saliva is about 180 times 
that of the sympathetic saliva, but it contains only '056 per cent, more salts. 
It will be noticed that, on the left side, the sympathetic saliva has '123 per cent, 
less salts than the chorda saliva; whilst, on the right side, the sympathetic saliva has 
only '061 per cent, less salts than the chorda saliva, i.e., the fall in the percentage of 
salts is greater on the side on wdiich the sympathetic saliva is more rapidly secreted. 
It is, however, just possible that this might have been due to a slight admixture of 
chorda saliva. 
The chief point, however, with which we are concerned is that, when chorda saliva 
is taken as a standard, the percentage of salts in sympathetic saliva is much 
higher than that which corresponds to its rate of secretion. 
In view of this fact, and of the fact that stimulating the sympathetic nerve causes 
a very great diminution in the amount of blood flowing through the gland, and in 
consequence a very great diminution in the supply of oxygen to the secretory cells, 
the possibility was suggested that if, in other ways, either the blood flow through the 
gland or the oxygen in the blood were diminished, the percentage of salts in saliva 
might be increased. We accordingly made some observations on these points. 
* Langley, ‘ Journal of Physiology,’ vol. 9, 1888, p. 59. 
