Bodily Labour upon the Discharge of Nitrogen. 447 



been made which might excite the heart. The standing observation 

 was made by getting out of bed as quietly as possible, and standing 

 upright for two or three minutes, during which I counted my pulse, 

 until I found that the quickening produced by the movement had sub- 

 sided. I then made the observation, often repeating it two or three 

 times. At night I remained standing for five or six minutes before 

 counting the pulse, and on lying down the same precaution was 

 observed. 



Respiration. — Observations in the two positions were also made 

 morning and evening, the same care being taken to ensure accuracy. 



I found it was not by any means an easy matter to count the respi- 

 ration without affecting its rate by the very act of doing so. The 

 plan eventually adopted was to stand with my watch in my left hand, 

 and my left wrist lightly pressing against the lower ribs ; with a little 

 practice I was able in this way to count the respirations almost 

 unconsciously. The figures given in the tables are as a rule the 

 mean of at least two observations. 



Temperature. — This was observed by means of a pair of clinical 

 thermometers, which had been carefully compared, and found to read 

 accurately together. The figures all indicate Fahrenheit degrees, and 

 are something less than one-tenth of a degree too high ; this being the 

 error of the instruments, no readings were taken under five minutes, 

 and most of them were over ten. I previously found by careful 

 experiment that three minutes would suffice for either of the ther- 

 mometers to attain the maximum temperature. 



The observations were taken in the mouth and axilla, great care 

 being taken to secure the proper position of the instruments ; any 

 doubtful observations were always repeated. I occasionally also took 

 the temperature of the rectum. Besides the morning and evening 

 observations, I took the temperature of the mouth frequently during 

 the exercise and at other times, when for some reason or another I 

 have thought it desirable to do so. The exact times at which all these 

 observations were made, together with notes on any which seemed to 

 require explanation, will be found recorded in the tables. 



The Body-Weight. — This was taken morning and evening on an 

 Avery's machine, weighing to ounces. On the days of exercise T 

 made two additional observations, one just before starting, and another 

 on returning. 



There are several points connected with the accurate determination 

 of the body-weight which are of very great importance in all investi- 

 gations of this kind, and which may not be out of place here. 



There is of course no difficulty whatever in determining the body- 

 weight at any given time, but I have learned from long experience 

 that it is not so easy to make what T may call a " fair " observation. 

 It will be obvious from an inspection of the tables that the variations 



