COMPOSITION OF EGGS. 201 



their nutrition, and which are required for the production of 

 animal heat. 



The yolk and albumen of eggs are in the same relation as 

 food for the embryos of oviparous animals, that milk is to the 

 young of Mammalia, and afford another example of mixed 

 food being provided as the most perfect nutrition. 



COMPOSITION OF FOWLS' EGGS. 



White. Yolk. 



Water, .... 80.0 . . . 53.73 



Albumen, .... 15.5 . . . 17.47 



Mucus, .... 4.5 Yellow Oil, . 28.75 



Salts, 4.0 ... 6.0 



Experiments illustrating the same principle have been per- 

 formed by Magendie and others. Dogs were fed exclusively 

 on sugar and distilled water. During the first seven or eight 

 days they were brisk and active, and took their food 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 six 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 experiments. The ani- 

 mals 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 appear- 

 ances 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 phenomena produced were the same, 

 except that no ulceration of the cornea took place : the effects 

 were also the same with butter. Tiedemann and Gmelin ob- 

 tained very similar results. They fed different geese, one with 

 sugar and water, another with gum and water, and a third 

 with starch and water. All gradually lost weight. The one 

 fed with gum died on the sixteenth day ; that fed with sugar 

 on the twenty-second ; the third, which was fed with starch on 

 the twenty -fourth ; and another on the twenty-seventh day ; 

 having lost, during these periods, from one-sixth to one-half of 

 their weight. The experiments of Chossat and Letellier prove 

 the same ; and in men, the same is shown by the various dis- 

 eases to which they who consume but little nitrogenous food 

 are liable, and especially, as Dr. Budd has shown by the affec- 

 tion of the cornea which is observed in Hindoos feeding almost 



