338 A MANUAL OF PHYSIOLOGY 



and which holds good in the dog and the rabbit, breaks down 

 before a wider induction. For in the cat the sympathetic 

 saliva of the submaxillary gland, although much more 

 scanty, is more watery than the chorda saliva (Langley), 

 which, however, is by no means viscid ; and the two secre- 

 tions differ far less than in the dog. In accordance with 

 this functional similarity, there is a much smaller difference 

 in the action of atropia on the two sets of fibres in the cat 

 than in the dog, although even in the cat the sympathetic is 

 less readily paralyzed than the chorda. 



In their secretory action there is not even an apparent 

 antagonism in the cat, with minimal stimulation of both 

 nerves, which causes as much secretion as would be pro- 

 duced if both were separately excited. Further, even in the 

 dog, after prolonged stimulation of the sympathetic, the 

 submaxillary saliva is no longer viscid, but watery, the pro- 

 portion of solids, and especially of organic solids, being 

 much lessened, as it also is in chorda saliva after long 

 excitation. When the cerebral nerve of the resting gland 

 is strongly excited, it is found that up to a certain limit the 

 percentage of organic matter in a small sample of saliva 

 subsequently collected during a brief weak excitation 

 increases with the strength of the previous stimulation ; 

 this is also true of the inorganic solids. But there is a 

 striking difference when the experiment is made on a gland 

 after a long period of activity ; here increase of stimulation 

 causes no increase in the percentage of organic material, 

 while the inorganic solids are still increased. In both cases 

 the absolute quantity of water, and therefore the rate of flow 

 of the secretion, is augmented. 



All this points to the same conclusion as the microscopic 

 appearances in the gland-cells, that the cells during rest 

 manufacture the organic constituents of the secretion, or 

 some of them, and store them up, to be discharged during 

 activity. The water and the inorganic salts, on the other 

 hand, seem rather to be secreted on the spur of the moment, 

 so to speak, and not to require such elaborate preparation. 

 And it has been stated that when the chorda tympani is 

 stimulated with currents of varying strength, the quantity of 



