
1890.] : Physiology. oð 
tion increases the percentage of Cl in the saliva, which confirms the 
results of Heidenhain and of Werther. Again, if the rate of secretion 
remain unchanged, increasing the quantity of NaCl in the blood, as 
by injection of a ten per cent. NaCl solution into the jugular vein, 
increases the Cl contents of the saliva. The Cl increase in the saliva 
is here more rapid than that of the blood. If both factors vary 
simultaneously, the results vary; but it seems that a moderate change 
in the NaCl contents of the blood can overcome a considerable 
change in the rate of secretion. The percentage of NaCl in the 
saliva reached as high as .627, but never equaled that of the blood. 
Langley and Fletcher in a paper presented to the Royal Society, and 
not yet printed,! while in general confirming the results of Novi, make 
a study of numerous other influences affecting the secretion of salts, 
such as dyspnoea, clamping the carotid, bleeding, pilocarpine, atropin, 
lithium citrate, potassium iodide and potassium ferrocyanide. ‘‘ The 
general result of these experiments is to show that the secretion of 
water, of salts, and of organic substances are differently affected by 
different conditions, and that the percentage composition of saliva is 
determined by the strength of the stimulus, by the character of the 
blood, and by the amount of blood supplied to the gland. All, or 
nearly all, the arguments which have been adduced to prove that the 
secretion of organic substance is governed by special nerve-fibres, have 
their counterparts with regard to the secretion of salts, so that we 
might imagine at least three kinds of secretory fibres to be present. 
The experiments, on the whole, indicate that this complicated arrange- 
ment does not exist, but that the stimulation of a single kind of nerve- 
fibre produces varying effects according to the varying conditions of 
the gland cells.” 
1 See abstract in Proceedings of Royal Society, Vol. XLV., No. 273, p. 16. 
