546 DIGESTION. 



disappeared; the muscles were reduced to less than five-sixths of their 

 ordinary size; the stomach and intestines were much diminished, and 

 powerfully contracted; and the gall and urinary bladders filled with 

 fluids not proper to them. These were examined by M. Chevreul, who 

 found them to possess almost all the characters of the bile and urine of 

 herbivorous animals. The urine, in place of being acid, as it is in the 

 carnivora, was sensibly alkaline, and presented no trace of uric acid or 

 phosphates. The bile contained a considerable proportion of picromel, 

 like that of the ox and herbivora in general. The excrements con- 

 tained very little nitrogen, which they usually do in abundance. 



A second dog was subjected to the like regimen, and with similar 

 results. He died on the thirty-fourth day of the experiment. A third 

 experiment, having eventuated in the same manner, M. Magendie con- 

 cluded that sugar alone is incapable of nourishing the dog. In all 

 these cases, ulceration of the cornea occurred, but not exactly at the 

 same period of the experiment. He next endeavoured to discover, 

 whether these effects might not be peculiar to sugar; or whether non- 

 nitrogenized substances, generally considered nutritious, might not act 

 in the same manner. He took two young and vigorous dogs, and fed 

 them on olive oil and distilled water. For fifteen days they were ap- 

 parently well ; but, after this, the same train of phenomena supervened 

 as in the other cases, except that there was no ulceration of the cornea. 

 They died about the thirty-sixth day of the experiment. Similar ex- 

 periments were made with gum Arabic, and with butter one of the 

 animal substances that do not contain nitrogen. The ^results were 

 identical. 



Although the character of the excrements passed by the different 

 animals indicated that the substances were well digested, M. Magendie 

 was desirous of establishing this in a positive manner. Accordingly, 

 after having fed animals for several days on oil, gum, or sugar, he 

 opened them, and found that each of these substances was reduced to 

 a particular kind of chyme in the stomach ; and that all afforded an 

 abundant supply of chyle ; that from oil being of a manifest milky 

 appearance, and that from gum or sugar transparent, opaline, and 

 more aqueous than the chyle from oil ; facts which prove, that if the 

 various substances did not nourish the animals, the circumstance could 

 not be attributed to their not having been digested. These results, M. 

 Magendie thought, render it likely, that the nitrogen, found in different 

 parts of the animal economy, is originally obtained from the food. This, 

 however, is doubtful. We have no proof, that the animals died simply 

 from privation of nitrogen. It is, indeed, probable, that it had little 

 or no agency in the matter, for there seems to be no sufficient reason 

 why it should not have been procured from the air in respiration, as 

 well as from that contained between the particles of the sugar, where 

 this substance was administered. It must be recollected, moreover, 

 that the subjects of these experiments were dogs; animals which, in 

 their natural state, are carnivorous, and, in a domestic state, omni- 

 vorous ; and that they were restricted to a diet foreign to their nature, 

 and one to which they had not been accustomed. Ought we, under such 

 circumstances, to be surprised, that they should sicken, and fall off? 



