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



We have made observations on twenty-five dogs and twenty cats. 

 The results in the dog are fairly constant, although from the nature 

 of the investigation, it is obvious that it is difficult rigorously to 

 ensure that all experiments shall be done under exactly the same con- 

 ditions : in the cat on the other hand the results at first sight appear 

 less constant. This is however, not surprising when we consider the 

 differences which are met with in the submaxillary saliva in the two 

 cases. In the dog there is a marked difference between the saliva 

 secreted on stimulation of the chorda and that secreted on stimu- 

 lation of the sympathetic, whereas in the cat the difference is not 

 nearly so great, both kinds of saliva resembling the chorda -saliva of 

 the dog; indeed the sympathetic saliva of the cat is generally dist- 

 inctly more watery than the chorda -saliva, although this difference 

 is by no means always so clearly marked. That is to say, the sym- 

 pathetic-saliva of the cat is sometimes very watery and sometimes 

 less so, and it is probable that these alterations in the nature of the 

 secretion and of the secretory processes in the cat's submaxillary may 

 account for the fact that the electrical changes are less constant than 

 in the dog. 



Method. 



The animal having been chloroformed , the roof of the skull, half- 

 way between the posterior margin of the orbit and the external occi- 

 pital protuberance, was pierced by a small trephine, a little to the 

 right of the middle line, and the dura mater divided. A hook suitably 

 curved, resembling a full -sized aneurism needle, was how inserted 

 between the dura mater and the brain until its point had passed 

 well round to the base of the skull. The handle was then depressed, 

 traction being made in an upward direction in such a manner as 

 to divide the crura cerebri (as was verified post mortem in a number 

 of cases). 



The animals were now curarized, a cannula having been placed in 

 the trachea, and artificial respiration was kept up. The chorda tympani 

 and the cervical vago- sympathetic were then exposed in the usual 

 manner. The vago -sympathetic was ligatured, and the cephalic end 

 arranged for stimulation. The lingual nerve was as a rule divided 



