16 iiodoe: 



toward end of experiment. At its close the muscles 

 were beginning to pass into rigor mortis. 



This closes the series of experiments upon frogs. It 

 is desirable, for a more general application of the results 

 above detailed, to ascertain whether they hold good 

 for some other animal. Experience has shown that 

 the most marked results are to be expected from experi- 

 ments in which the condition of the animal is most 

 nearly normal. I think 1 am justified in distrust- 

 ing the influence of curare; from the following 

 experiment, chloroform also would seem to be a dis- 

 turbing factor. A cat was killed with chloroform, and 

 several of the spinal ganglia were examined. Many 

 of the cells were found to show considerable vacuola- 

 tion, strikingly similar to that produced by stimula- 

 tion. The point needs further investigation, but it is 

 not altogether improbable that a substance which 

 produces such marked physiological effects may also 

 give rise to histological changes in nerve centers. 

 However this may be, it was determined not to run 

 any risk of complicating matters by the use of anaes- 

 thetics. A mode of producing insensibility without 

 the use of drugs was accordingly resorted to. 



Themethod^ adopted consists in trephining the skull 

 at about the point of greatest convexity and a centi- 

 meter to one side of the middle line. A small slit is made 

 in the dura, and through this a blunt glass rod is thrust 

 directly to the floor of the skull, and worked carefully 

 across along the floor to the opposite side. The crura 

 are thus severed at their entrance to the cerebrum ; 

 and if successful, complete anaesthesia, with normal 



' The method was obtained from a paper entitled "On the Renal 

 Circulation ilurint: Fever" (Walter Mendelson, Am. J. M. Sc, Phila. 

 1883), where the method is credited toLudwig. 



