498 



THE SALIVARY GLANDS. 



Parotid Gland Dog Stimulation of the Sympathetic after Stimulation 

 of Jacobson's Nerve. 



Saliva flow every 

 30 sees, in mm. 

 Nerve stimulated 



35 

 J. 



14 1 3 



000 



Sy. 



76 



minutes 



32 



J. 



Sy.Sy. J. 



10 



Sy. 



A brief rapid increase in the flow of saliva is obtained by stimulating 

 the sympathetic during the action of pilocarpine and other alkaloids 

 which cause a continuous free flow of saliva. After the first rapid rise 

 the secretion becomes slower, and in the parotid gland of the dog stops 

 altogether ; in the submaxillary gland the secretion slowly continues. 



Parotid Gland Dog Pilocarpine Injected. 

 Rise of saliva 6 6 35 7 3 



stim. symp. 



EFFECT OF PKOTRACTED STIMULATION ON THE AMOUNT AND 

 PERCENTAGE COMPOSITION OF SALIVA. 



During protracted stimulation, as was shown by Becker and Ludwig, 1 

 the percentage of solids in the saliva diminishes. They found a marked 

 diminution in the percentage of organic substance ; and generally, but 

 not always, some diminution in the percentage of salts. The most striking 

 experiment given by them is the following. The chorda tympani was 

 stimulated, and successive portions of the saliva were analysed : 



The decrease in the percentage of salts is probably connected, as 

 Heidenhain has pointed out, with the slower rate of secretion of saliva 

 in the later portions collected. 



Heidenhain 2 showed that the percentage of solids sinks during pro- 

 tracted secretion, not only in chorda saliva, 3 but also in sympathetic 

 submaxillary saliva. In the following experiment the sympathetic was 

 stimulated at short intervals during five and a half hours ; the first and 

 the last portions of saliva collected were analysed : 



1 Ztschr.f. rat. Med., 1851, N. F., Bd. i. S. 278. 



2 Stud. d. physiol. Inst. zu Breslau, Leipzig, 1868, S. 65. 



3 We have to refer so frequently to the saliva obtained from the submaxillary gland 

 (1) by stimulating the chorda tympani, (2) by stimulating the sympathetic, (3) by 

 injecting pilocarpine that we are driven to adopt the terms, chorda saliva, sympathetic 

 saliva, and pilocarpine saliva, for the saliva obtained respectively in these circumstances. 



