On the Practical Measurements of Temperature. 231 



moderate degree of traction is made. Fortunately this condition of 

 traction upon a solid body already engaged in the intestinal tube can 

 but rarely come into operation in the animal body, or it would un- 

 doubtedly prove peculiarly difficult to overcome. 



Mechanical irritation of the lower mouth or upper mouth of the 

 fistulous intestine, if persisted in, developed a powerful peristalsis 

 which caused the rapid passage of a solid body through the fistula 

 and its expulsion by the lower opening. Thus if the animal was 

 induced — which it readily was — to lick the mouth of the fistula 

 after the sound had been inserted in the upper opening, expulsion 

 from the lower opening occurred in four to eight minutes. By 

 moving a glass rod — passed within the mouth of the fistula — gently 

 round or in and outwards, the same result was occasionally pro- 

 duced, but not with the same speed or certainty. 



The consideration of the effect of electrical stimulation and of a 

 number of drugs, upon whose action I believe new light will be 

 thrown by this method of experimentation, I must leave to a future 

 paper. 



I have purposely avoided entering into a discussion of the physio- 

 logical rationale of the various phenomena I have described in this 

 communication, because they cannot find their full explanation in the 

 examination of a fistulous animal. This explanation must be sought 

 by experiment of another character, and although much has been 

 rendered clear to me by the analytical research I have already made, 

 other points are still lacking their complete elucidation. Until the 

 latter research appears, I likewise postpone reference to the literature 

 of the subject. 



To the Royal Society, which presented me with a donation in aid of 

 this research, and to Prof. Hugo Kronecker, of Berne, who most kindly 

 placed his laboratory at my disposal for its accomplishment, my best 

 thanks are due, and I gladly take this opportunity of recording them. 



" On the Practical Measurements of Temperature. Experi- 

 ments made at the Cavendish Laboratory, Cambridge." 

 By H. L. CALLENDAR, B.A., Scholar of Trinity College, 

 Cambridge. Communicated by J. J. Thomson, F.R.S., 

 Professor of Experimental Physics at the Cavendish 

 Laboratory, Cambridge. Received June 9. — Read June 10> 

 1886. 



(Abstract.) 



The experiments were undertaken with a view to investigate the 

 possibility of establishing strictly comparable standards for high 

 temperature .measurements for which the air thermometer is in- 



