291 



from the body. It was further desired to operate on an animal in 

 what might be considered its natural condition as to food. Accord- 

 ingly one that had been running at large was selected, and the 

 following experiment performed : 



Exp. 2. Into the left carotid artery of a small cocker dog was 

 inserted a canula with a stopcock. The animal was then placed so 

 as to allow the blood to flow directly into the boiling acidulated 

 water. The clear filtered liquid from this blood became of a yellow 

 tint on being boiled with soda, and gave a red precipitate with the 

 sulphate of copper and potash, thereby indicating the presence of 

 sugar. Two ounces of blood from the same animal were similarly 

 tested after the blood had stood twenty-four hours in a room of 

 moderate temperature, and the result obtained was the same as 

 with the first portion. 



The next experiment was made on an animal under conditions, 

 as regards food, unfavourable for the production of sugar. In order, 

 too, to avoid any chance of injuring the sympathetic nerve during 

 the operation, and thereby favouring the formation of sugar in the 

 body, the blood was withdrawn from the right femoral artery instead 

 of the carotid. The following are the particulars of the experi- 

 ment : 



Exp. 3. A good-sized dog was fed solely on flesh during four 

 days. Three hours after the last meal, which consisted of half a 

 pound of boiled horseflesh, 1^ oz. of blood was permitted to flow 

 from the femoral artery directly into the boiling mixture. The 

 solution obtained from this blood, as in the other cases, contained 

 sugar. Another portion of blood, after standing three hours, was 

 tested in the same way, and, as far as could be judged by the eye, 

 contained a similar proportion of sugar. 



In neither of the preceding cases was the amount of sugar in the 

 blood quantitatively determined, as I had already done so on many 

 previous occasions ; and I knew that in healthy arterial blood it 

 varied according to the state of the digestion, and the kind of food, 

 from an inappreciable quantity up to 0'24 percent.* 



Having been now satisfied that sugar is to be found in the blood 

 of healthy animals at the very moment of its withdrawal from the 



* " On the Physiology of Saccharine Urine," by Geo. Harley, M.D., British 

 and Foreign Med. Chir. Rev. July 1857, p. 191-204. 



