FOODS AND DIET. 217 



and drink as usual ; but in the course of the second week they began to 

 get thin, although their appetite continued good, and they took daily 

 between seven and eight ounces of sugar. The emaciation increased 

 during the third week, and they became feeble, and lost their activity 

 and appetite. At the same time an ulcer formed on each cornea, followed 

 by an escape of the humors of the eye : this took place in repeated ex- 

 periments. The animals still continued to eat three or four ounces of 

 sugar daily ; but became at length so feeble as to be incapable of motion 

 and died on a day varying from the thirty-first to the thirty-fourth. On 

 dissection, their bodies presented all the appearances produced by death 

 from starvation'; indeed, dogs will live almost the same length of time 

 without any food at all. 



When dogs were fed exclusively on gum, results almost similar to.the 

 above ensued. When they were kept on olive oil and water, all the phe- 

 nomena produced were the same, except that no ulceration of the cornea 

 took place ; the effects were also the same with butter. The experi- 

 ments of Ohossat and Letellier prove the same ; and in men, the same 

 is shown by the various diseases to which those who consume but little 

 nitrogenous food are liable, and especially by the affection of the cornea 

 which is observed in Hindus feeding almost exclusively on rice. But it 

 is not only the non-nitrogenous substances, which, taken alone, are in- 

 sufficient for the maintenance of health. The experiments of the Acad- 

 emies of France and Amsterdam were equally conclusive that gelatin 

 alone soon ceases to be nutritive. 



III. Effect of Too Much Food. 



Sometimes the excess of food is so great that it passes through the 

 alimentary canal, and is at once got rid of by increased peristaltic action 

 of the intestines. In other cases, the unabsorbed portions undergo putre- 

 factive changes in the intestines, which are accompanied by the produc- 

 tion of gases, such as carbonic acid, carbu retted and sulphuretted 

 hydrogen, and a distended condition of the bowels, together with symp- 

 toms of indigestion, is the result. An excess of the substances required 

 as food may undergo absorption. It is a well-known fact that numbers 

 of people habitually eat too much, and especially of nitrogenous food. 

 Dogs can digest an immense amount of meat if fed of ten, and the amount 

 of meat taken by some men would supply not only the nitrogen, but also 

 the carbon which is requisite for an ordinary natural diet. A method 

 of getting rid of an excess of nitrogen is provided by the digestive pro- 

 cesses in the duodenum, to be presently described, whereby the excess of 

 the albuminous food is capable of being changed before absorption into 

 nitrogenous crystalline matters easily converted into urea and so easily 

 excreted by the kidneys, affording one variety of what is called luxus 



