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Mr. J. B. Power. 



[Feb. 16, 



I shall now briefly state the mode of collecting the excretion which 

 I adopted. Having first tested the atmosphere of the ward in which I 

 was about to operate, to ascertain that it did not contain free am- 

 monia in any quantity, I placed upon one of my hospital beds an 

 india-rubber sheet, and over it another sheet of pure linen, upon 

 which the person experimented upon lay. Over his body was placed a 

 wooden cradle or canopy, covered outside with a thick felt, and lined 

 inside with linen, which coverings were to be carefully adjusted round 

 his neck. To raise the temperature within the canopy I used the 

 lamp-furnace invented by the late Surgeon-Major Wyatt, the flue 

 from which fitted accurately through a hole in the coverings guarded 

 by a wooden ring. Considering the spirit lamp of Wyatt's furnace 

 objectionable for many reasons, I substituted a Bunsen gas-burner. 

 To insure the regular renewal of the air within the canopy, and to 

 prevent its saturation, as well as to collect any free ammonia which 

 might be evolved, I introduced a tube leading from a Bunsen air- 

 pump, which tube was connected with two glass towers filled with 

 large glass beads, and charged with half an ounce of dilute hydro- 

 chloric acid of known strength. Through another hole in the canopy 

 I introduced a hydrometer, by which I was enabled to observe the 

 temperature, and calculate the degree of saturation of the atmosphere 

 within. As the gas, water, and reagents employed contained some 

 small portion of nitrogen, my first task was to ascertain the constant 

 error arising from this source. To effect this I performed three blank 

 experiments, omitting only the introduction of the person to be 

 experimented upon. The result was that I obtained a small quantity 

 of nitrogen, nearly equal in each case, viz., 0*066, 0*066, and 0'061, 

 and having a mean value of 0*064 grm., that being the total amount 

 collected in one hour under the experimental conditions. The water 

 I used was Yartry water, it being the water supply to my hospital, 

 and when I used it unfiltered I employed the above number as a 

 constant. As it would be necessary when I wished to get rid of 

 epithelium to filter the portion of the bath water I took for analysis, 

 I made three similar blank experiments, using filtered Vartry water, 

 and obtained another constant, amounting to 0*0408 grm. of nitrogen, 

 which I used in all such experiments. The method employed for 

 estimating the nitrogen will be described later on. In the nine experi- 

 ments in which I estimated the chlorides I took the precaution of 

 finding the amounts of chlorides present in the Yartry water on that day, 

 as I found the quantity of chlorides present in it liable to periodic 

 variations. 



I now commenced a series of experiments upon myself, with the 

 assistance of my clinical clerk, Mr. Clune. One of these I shall 

 describe : — I first took a sponge bath for the purpose of removing 

 loose epithelial scales, as well as minute fibres from the underclothing, 



