132 W. M Bayliss and J. R. Bradford, 



that it consists really of two opposite phases, each of which at different 

 times may predominate and obscure the other. Thus although in the 

 dog, it is usual to find on sympathetic stimulation a slow and small 

 variation opposite in sign to the main chorda -effect, in the cat, this 

 is quite the exception and we have only met with it in three or four 

 cases. The usual effect in the cat is a deflection of like sign to the 

 chorda-deflection, and like it large in amount and frequently di-phasic. 

 There are however a few points of difference. The first phase of the 

 chorda -variation is usually small, as compared with the chorda -effect 

 in the dog, owing to the presence of a large second phase ; but the 

 sympathetic -variation shows a much larger first phase (i. e. outer sur- 

 face of gland negative to hilus); the spot of light frequently travelling 

 off the scale, as in the case of the chorda of the dog, generally ac- 

 companied by a free flow of saliva. On the other hand when the first 

 phase was small in amount owing to the presence of a second phase, 

 the amount of saliva secreted was both smaller in amount and more 

 viscid. These results were frequently to be observed in the same 

 animal, for at one time a large first phase and free secretion would 

 be observed, ^at another a di-phasic variation, and the saliva much 

 less in amount and more viscid in character. In two cases in which 

 excitation of the sympathetic gave a pure second phase, no secretion 

 was observed, although the electrical effect was very marked. In one 

 case although a pure second phase only was observed, secretion was 

 observed, although of small amount. 



Thus the sympathetic -variation in the cat rather resembles the 

 chorda- than the sympathetic -effect in the dog, but it resembles still 

 more closely the chorda- effect in the cat. 



Atropine. — The action of atropine on the sympathetic -variation 

 in the cat also shows a marked difference compared with its action 

 upon that of the dog. In the latter as we have seen the electrical 

 effect is very refractory towards atropine, but this is not the case in' 

 the cat, in which atropine in small doses abolishes the first phase of 

 the sympathetic -variation, so that on stimulation of the nerve, either 

 no electrical effect is produced, or if the dose of atropine be small, 

 and the excitation be applied soon after its injection, the second phase 

 only is observed; either with no accompanying secretion, or with an 



