1877.] 



Sugar in relation to the Blood. 



315 



fluence. It had hitherto been asserted that the blood of the right side 

 of the heart was in a notably different condition as regards the amount 

 of sugar it contained from that of the arterial system, an error which I 

 discovered arose from the non-observance of certain precautions in the 

 mode of obtaining the blood for examination from the respective parts of 

 the vascular system. Whilst the arterial blood had been collected during 

 life, it was customary to collect that from the right side of the heart, 

 without any special haste, after the destruction of the life of the animal. 

 During the period thus allowed to elapse between the moment of death 

 and the collection of the blood, an alteration occurs from the post mortem 

 production of sugar in the liver, which causes the blood to assume an 

 extent of saccharine impregnation which does not naturally belong to it 

 during life, and which had failed to be recognized in its true light. I 

 gave analyses which show that what was formerly taken as representing 

 the natural condition of the blood of the right side of the heart fur- 

 nished from *50 to *94 per cent., or, as it is more convenient to state 

 it, 5-0 to 9-4 per 1000 of sugar, the blood from the carotid artery of the 

 same animals, collected during life, having contained what I described as 

 a trace of sugar. Other analyses, three in number, were given, repre- 

 senting the true condition of the blood belonging to the right side of the 

 heart during life, and the results indicated from -47 to '73 per 1000 as 

 the amount of sugar. 



Bernard has recently published some communications entitled " Cri- 

 tiques experimentales sur la glycemie," in the Comptes E-endus de 

 l'Academie des Sciences de Paris. His statements are founded upon a 

 method of analysis which is not only strikingly devoid of precision as a 

 quantitative analytical process, but in itself of a nature calculated to give 

 rise to a fallacious result. 



The process adopted by Bernard is as follows : — He makes use of a 

 Fehling's solution, titrated to render 1 c. c. equivalent to 5 milligrammes, 

 of sugar. He withdraws with a syringe, or collects as it flows from the 

 vessel in a weighed porcelain capsule, a determined quantity — 10, 15, or 

 25 grammes of blood. To this be adds an equal weight of sulphate of 

 soda in small crystals, with a few drops of acetic acid, and heats imme- 

 diately over the flame of a gas-burner or spirit-lamp, to coagulate the 

 albuminous and colouring matters. On account of the relatively small 

 quantity of sugar to be dealt with, he only uses for the analysis 1 c. c. of 

 the standard copper solution. This he heats in a small glass flask, after 

 having added 20 to 25 c. c. of a fresh concentrated solution of potash, 

 and drops into it the liquid to be tested till decolorization is effected. 

 From the suboxide remaining dissolved, and the liquid being thus free 

 from precipitate, the attainment of the point of decolorization is easy to 

 be perceived. Observation, he says, has shown that the relation of 

 volume of liquid yielded to weight of a mixture of equal parts of blood 

 and sulphate of soda is ; in other words, that 50 grms. of sulphate of 

 soda and of blood give 80 c. c. of trial liquid. The estimation having 



