THE PRINCIPLE OF VITAL AFFIXITY. 325 



living body were useful, as this theory supposes, only by yielding to the simply 

 chemical action of oxygen, and so giving off caloric, we do not see how these 

 changes in diabetes should interfere with that ofiice, or how they should involve 

 so great derangement of the system, and particularly so much gradual wasting of 

 all the textures. But if the starch taken into the system is liable to transforma- 

 tions resulting fi-om vital affinities, and in which albumen is generated, then we 

 can understand, that a disease in which starch seems to lose all tendency to vital 

 action, and is rapidly thrown off, should be attended with this emaciation and 

 debility. 



4. When we attend to the phenomena of Lithiasis, i. e., the morbid forma- 

 tion of uric acid, and the effects of different kinds of diet upon it, we meet with 

 facts hardly to be reconciled to the idea of the albuminous ingesta being all des- 

 tined for nutrition, and the non-azotised for combination with oxygen and excre- 

 tion. It is well known, that Liebig pointed out that this diseased state depends 

 on imperfect oxidation of the albuminous matter in the blood, which is destined 

 to excretion (causing a formation of uric acid, when a fuller oxidation would pro- 

 duce urea and carbonic acid) ; and that he supposed all the albuminous matter 

 which unites with oxygen in the blood, to be the product of absorption from the 

 textures, the recently introduced albumen being, according to his theory, destined 

 for nutrition only. Hence he argued, that a vegetable diet, increasing the quan- 

 tity of non-azotised ingredients of the blood, with which the oxygen most readily 

 unites, would leave less oxygen for the azotised or albuminous constituents, and 

 aggravate the disease. But experience has shewn, particularly since the obser- 

 vations of Magendie were published, that the disease is more generally mitigated 

 by a vegetable diet, under which, as it would appear, the whole quantity of azo- 

 tised matter in the blood and in the urine is diminished, and the oxygen taken in 

 is sufficient for its full oxidation. And the experiments of several authors have 

 shewn, that the quantity of azotised matter thrown off by the kidneys increases 

 greatly (may be nearly doubled) within a few hours after highly azotised food 

 is taken. From which facts it would appear, that the azotised matter thrown off 

 by the kidneys, is derived not merely from absorption of the textures, but like- 

 wise directly from the ingesta ; and if so, the distinction of the azotised ingesta, 

 destined only for nutrition, and the non-azotised, destined only for excretion, is 

 not observed by nature ; and it becomes extremely probable, that, as part of the 

 albuminous ingesta are excreted, so a portion of fresh albuminous matter is formed 

 in the blood, and applied, in the &-st instance, to the nutrition of textures. 



IV. It is at all events certain, that Gelatin is formed in the living body, and 

 its composition, as stated by Liebig, Ci„s Ni8 H^j 0„ 

 or by Mulder, C^y, Nis Hgo O45 



compared with that of albumen. Cm Nis Hios O^a 



VOL. XVt. FART III. 4N 



