Dr. Pavy on the metamorphosis of Saccharine Matter. 147 



This acid reaction of decomposing blood is only observable in 

 that which was previously pretty largely impregnated with sugar. 

 It appears to be owing to the formation of lactic acid. Certainly, 

 it cannot be due to carbonic acid, for the reaction remains after 

 exposure to a boiling temperature. 



The disappearance of sugar in the manner just pointed out does 

 not depend on the oxygen of the air, except in so far as this agent is 

 concerned in exciting the decomposition of the azotized constituents 

 of the blood ; for the sugar disappears as rapidly when there is a 

 small, as when there is a large amount of surface exposed to the air. 

 But if the air be carefully and completely excluded, no signs of de- 

 composition of the animal parts of the blood are to be observed, and 

 under these circumstances the sugar also remains. The disappear- 

 ance of sugar is more rapid where the fibrine and corpuscles are pre- 

 sent, than when the serum is exposed alone ; and in accordance 

 with this, the blood in the one case undergoes decomposition much 

 sooner than in the other — a fact easily intelligible from the greater 

 amount of azotized ingredients present. 



If blood normally impregnated with saccharine matter be placed 

 aside until signs of incipient decomposition are observed, and the 

 sugar is beginning to disappear, exposure to a current of oxygen 

 rapidly completes the total disappearance of the saccharine con- 

 stituent. In this observation we have a further illustration of the 

 analogy that appears to exist, in the nature of the metamorphosis of 

 sugar as a physiological process, and that which takes place chemi- 

 cally under the influence of an azotized compound, whose elemen- 

 tary particles are in a state of molecular transition. During life, 

 the higher organic constituents of the blood are capable of under- 

 going the changes of assimilation on exposure to contact with 

 oxygen, and there is a considerable destruction cjf sugar effected ; 

 for a short jjeriod after death these azotized constituents remain 

 stationary and uninfluenced by oxygen, and with this, there is a 

 corresponding suspension of the transformation of sugar ; but finally, 

 the animal matter of the blood on contact with oxygen, especially 

 during a warm temperature, assumes a state of decomposition, the 

 molecular changes of which again excite the destruction or meta- 

 morphosis of saccharine matter. 



The sugar disappears far less rapidly from diabetic blood under 

 the influence of exposure to the atmosphere, than from healthy 

 right-ventricular blond. From these, and a few other observations 

 which he has as ytt been able to make on the blood in Diabetes 

 Mellitus, the author, were he to hazard an opinion on the nature of 

 that obscure disease, would be disposed to say that there appears to 

 be a modification of sugar jiroduced by the liver, which is not suscep- 

 tible of undergoing the normal process of destruction in the animal 

 system, and which, therefore, accumulating in the blood, is elimi- 

 nated by the kidneys, 'i'he experiments of Bernard have shown 

 that yegetalile glucose (grajje-sugar) is not susceptible of destruc- 

 tion in the processes of animal life, unless converted into animal 

 glucose by the agency of the liver. Diabetic sugar would there- 



