146 Royal Society : — 



of assimilation on contact with oxygen as in the living animal, the 

 sugar in great part disappears, but so soon as the librine is sepa- 

 rated by spontaneous coagulation, and the blood has thus lost its 

 vital characteristics, oxygen is no longer capable of exerting any 

 metamorphosing influence on its saccharine ingredients. 



If the molecular changes occurring during the decomposition of an 

 azotized substance be capable of converting sugar into lactic acid, why 

 should not the molecular changes occurring during the building-up 

 or elaboration of this same nitrogenized compound efl!'ect the same ? 

 Indeed, we have seen that the process of destruction is carried on to 

 a certain extent in the systemic capillaries, and more especially 

 in those of the chylo-poietic viscera, where the molecular changes 

 of nutrition are also correspondingly carried on with greater activity 

 than elsewhere. So that analogy and experiment would tend to 

 show that the physiological destruction of sugar is owing to a pro- 

 cess similar to fermentation induced by the molecular changes 

 occurring in the nitrogenized constituents of the animal during life. 

 And, in accordance with this, we find lactic acid present in the 

 system, and largely separated from arterial blood by the muscular 

 tissue, and the secerning follicles of the stomach. 



As regards the lactic acid fermentation, it is well known that 

 the presence of an alkali favours, whilst that of an acid retards the 

 process. In two experiments on animals, the author injected car- 

 bonate of soda and phosphoric acid into the circulating current, and 

 observed in the case of the latter that sugar immediately accumu- 

 lated in the blood. 



The preceding observations refer more especially to the changes 

 that take place in the saccharine ingredient of the blood during 

 life ; and the author next proceeds to notice some interesting phse- 

 nomena observable during the decomposition, and even the sponta- 

 neous coagulation of blood containing sugar. 



If the blood of an animal normally impregnated with sugar be 

 placed aside, and allowed to undergo spontaneous coagulation, on 

 examining separately the serum and clot on the following day, it 

 will be found, that although the serum may be largely saturated 

 with sugar, the clot is entirely, or almost entirely destitute of it. 

 Now, as the clot is moist and remains to a certain extent infiltrated 

 with the serum from which it has partially separated, it would 

 appear that even the molecular changes arising from the sponta- 

 neous coagulation of the blood are sufficient to effect the destruc- 

 tion of normal animal sugar. And this conclusion is strengthened 

 by the fact, that in diabetic blood (the sugar of which, as would 

 appear from other considerations also, is not so susceptible of 

 metamorphosis as the healthy variety) the sugar does not disap- 

 pear to a similar extent in the clot. 



Under the changes of the decomposition of blood, normal animal 

 glucose is very readily metamorphosed. The rai)idity of the meta- 

 morphosis depends on the activity of the decomposition of the 

 animal substances present, and when the destruction of the sugar is 

 complete the blood has assumed an acid reaction. 



