NECESSITY OF A VARIED DIET. 193 



able at first to perform only about two-thirds of the labor accomplished by the English. 

 It was suspected that this was due to the more substantial diet of the English, which 

 proved to be the fact ; for, when the French laborers were subjected to a similar regi- 

 men, they were able to accomplish an equal amount of work. In all observations of this 

 kind, and they are very numerous, it has been shown that an animal diet is much more 

 favorable to the development of the physical forces than one consisting mainly of vege- 

 tables. 



Climate has an important influence on the quantity of food demanded by the system. 

 It is generally acknowledged that the consumption of all kinds of food is greater in cold 

 than in warm climates, and almost every one has experienced in his own person a con- 

 siderable difference in the appetite at different seasons of the year. Travelers' accounts 

 of the quantity of food taken by the natives of the frigid zone are almost incredible. 

 They speak of men consuming over a hundred pounds of meat in a day ; and a Russian 

 admiral, Saritcheff, mentions an instance of a man who, in his presence, ate at a single 

 meal a mess of boiled rice and butter weighing twenty-eight pounds. Although it is 

 difficult to regard these statements with entire confidence, the general opinion that the 

 appetite is greater in cold than in warm climates is undoubtedly well founded. Dr. 

 Hayes, the Arctic explorer, states, from his personal observation, that the daily ration 

 of the Esquimaux is from twelve to fifteen pounds of meat, about one-third of which is 

 fat. On one occasion he saw an Esquimau consume ten pounds of walrus-flesh and 

 blubber at a single meal, which lasted, however, several hours. The continued low 

 temperature he found had a remarkable effect on the tastes of his own party. With the 

 thermometer ranging from 60 to 70 Fahr., there was a continual craving for a 

 strong animal diet, particularly fatty substances. Some members of the party were in 

 the habit of drinking the contents of the oil-kettle with evident relish. 



Necessity of a Varied Diet. 



In considering the nutritive value of the various alimentary principles, the fact that 

 no single one of them is capable of supplying all the material for the regeneration of the 

 organism has frequently been mentioned. The normal appetite, which is our best guide 

 as regards the quantity and the selection of food, indicates that a varied diet is necessary 

 to proper nutrition. This fact is also exemplified in a marked degree in long voyages 

 and in the alimentation of armies, when, from necessity or otherwise, the necessary 

 variety of aliment is not presented. Analytical chemistry fails to show why this change 

 in alimentary principles is necessary, or in what the deficiency in a single kind of diet 

 consists; but it is nevertheless true that, after the organic constituents of the organism 

 have appropriated the nutritious elements of particular kinds of food for a certain time, 

 they lose the power of inducing the changes necessary to proper nutrition, and a supply 

 of other material is imperatively demanded. This fact is particularly well marked when 

 the diet consists in great part of salted meats, although it is also the case when any single 

 variety of fresh meat is constantly used. After long confinement to a diet restricted as 

 regards variety, a supply of other material, such as fresh vegetables, the organic acids, 

 and articles which are called generally anti-scorbutics, becomes indispensable ; otherwise, 

 the modifications in nutrition and in the constitution of the blood incident to the scor- 

 butic condition are almost sure to be developed. 



It is thus apparent that adequate quantity and proper quality of food are not all 

 that are required in alimentation ; and those who have the responsibility of n-irnlating 

 the diet of a large number of persons must bear in mind the foot that the organism de- 

 mands considerable variety. Fresh vegetables, fruits, etc., should be taken at the proper 

 seasons. It is almost always found, when there is of necessity some sameness of diet, 

 that there is a general craving for particular articles, and these, if possible, should be 

 supplied. This was frequently exemplified in the late war. At times when the diet was 

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