SECKETION OF SALIVA 213 



still obtained. Lastly, paint the chorda with the nicotine solution, 

 just at its entrance into the hilum, and again stimulate. No secretion 

 is obtained. 



Finally apply the electrodes to the hilum of the gland, when on 

 stimulation a free secretion will again be obtained. This experiment 

 with nicotine demonstrates the existence of nerve cells on the course 

 of the chorda fibres. Nicotine in minute doses is known to paralyse 

 nerve cells without injuring the nerve fibres, though in large doses it 

 paralyses nerve fibres as well. The experiment therefore proves that the 

 nerve cells in the submaxillary ganglion are not placed on the course 

 of chorda fibres running to the submaxillary gland. They are, in 

 fact, known to lie on the course of secretory fibres running to the 

 sublingual gland. The result of painting the chorda with nicotine 

 proves that the nicotine solution is not strong enough to paralyse the 

 nerve fibres. The absence of secretion on stimulation after the hilum 

 has been painted with nicotine proves that there are gland cells on 

 the course of the secretory fibres which are placed on the nerve at or 

 near its entrance into the hilum. This is further confirmed by 

 obtaining a secretion on subsequent stimulation at the hilum, for then 

 the post-ganglionic fibres are excited. 



