52 Innervation of the Glandular Elements 



chorda even in the presence of atropine, for it persisted when the 

 dilatation had passed off. The reasonable explanation was that the 

 parasympathetic transmitter, although unable to cause a secretion, 

 had increased, for some time, the excitability of the gland cells. It 

 has, in fact, been shown that acetylcholine in such quantities as can 

 be liberated from the chorda endings raises the excitability of the 

 submaxillary cells (Beznak and Farkas, 1936-37). 



Making use of the "true augmented secretion" it may be possible 

 to demonstrate a secretory effect of the sympathetic fibres even in 



020 



015- 



0010- 



005 



Fig. 3.5. Secretion from the sublingual glands of two cats in chloralose 



anaesthesia. 



Each column represents the amount of saliva in ml. collected over a io-minute period. The 

 high columns correspond to samples collected during nerve stimulation. In the experiment to the 

 left the chorda was excited during the first 30 seconds of a io-minute period. To the right: in the 

 fifth period the sympathetic was stimulated during the first minute (Emmelin, 1953). 



glands in which it is difficult to detect such an effect merely by 

 stimulating the nerve. 



3. The sympathetic stimulation, even if it does not cause a flow 

 of saliva, can change the composition of saliva secreted in response 

 to excitation of the parasympathetic fibres, but it may be necessary 

 to ascertain that this effect is not secondary to sympathetic vaso- 

 constriction. 



4. In glands showing a spontaneous secretion a real secretory 

 effect of the sympathetic fibres may manifest itself in the way 

 shown in Fig. 3.5. The sublingual gland of the cat secretes spon- 



