140 
MESSRS. J. N. LANGLEY AND H. M FLETCHER 
The injection of strong sodium chloride solution into the blood causes here, as in the 
previous experiment, an increase in the percentage of salts in the saliva secreted, and, 
taking the rate of secretion into consideration, there is an increase in the percentage 
of salts after each injection. But in neither experiment does the percentage of salts 
reach the maximum {'77 to ’78 per cent.) which may be obtained normally with a 
rapid secretion. It is possible, however, that, if a rapid secretion had been obtained, 
the normal maximum percentage of salts might have been exceeded. 
According to Klikowicz,"^ the blood, when strong sodium chloride solution is 
injected into the circulation, very rapidly gives up sodium chloride to the tissues, and 
takes up water from them.t From these causes combined, but especially from the 
former, the injection of sodium chloride into the blood does not lead to a corre¬ 
sponding increase in the percentage of salts in it. Thus, Klikowicz found that the 
injection of 21 grin, of NaCl—in 10 per cent, solution—into the blood of a Dog 
weighing 24 A kilos, only increased the percentage of Cl in the blood from ’301 to 
•435, and in the serum from ‘371 to ’554; the blood being taken two minutes after 
the end of the injection, which itself lasted live minutes. But the amount of NaCl 
injected, if simply added to the amount of blood in the animal, would increase the 
percentage of Cl in the blood by at least 1’2, if it all remained in the plasma, and by 
about half as much, if it were equally distributed between blood corpuscles and 
plasma. 
In our experiments, about twice as much NaCl per kilo, of body freight was 
injected as in Kltkowicz’s experiments. By the light of Klikowicz’s results we 
should suppose that in our experiments the percentage of salts in the plasma, during 
the collection of saliva, varied from 1 to 1'5 per cent. 
In Experiment 11, the injection of strong salt solution not only increases the per¬ 
centage of salts in the saliva, but also the percentage of organic substance; this is 
very markedly the case in V. In V. the small rate of secretion makes it unlikely that 
the salt solution exerts a stimulating action on the gland. An indirect action may 
take place by means of the blood vessels. The salt solution may diminish the normal 
blood flow through the gland, either by weakening the heart beat, or by counteracting 
the vaso-dilator effect of pilocarpin. And this would be sufficient to account for the 
rise in percentage of the organic substance, and for a part of the rise in percentage of 
the salts. 
Since it seemed possible that a mixture of the various salts found in saliva might 
have a greater effect than sodium chloride alone, we tried one experiment, injecting 
into the blood a sohition containing about 19 per cent, of the salts found in 
saliva, viz. :— 
* Klikowicz, ‘ Arcbiv f. Anat. u. Physiol. (Physiol. Abth.),’ 1886, p. 534. 
t The injection of strong sodium chloride caused the snh-maxillary gland in both of our experiments 
to become somewhat cedematous. 
