94 NUTRITION. 



oxygenated as at a later time when the nutritive operations 

 are comparatively slowly carried on, prove that this doctrine 

 is erroneous. 



Every one knows that food nourishes the body, and 

 that the tissues are nourished by the blood, and it is 

 generally believed that a high state of nutrition depends 

 upon a liberal diet. At the same time, however, we know 

 that the degree of nutrition exhibited by the body is not 

 dependent merely upon the quantity or quality of the food 

 introduced into the stomach, and absorbed and converted 

 into blood, but upon a number of circumstances besides. In 

 one individual much of the food taken may be excreted in 

 an altered form soon after it has been introduced into the 

 system, while in another a large proportion may become 

 converted into tissue and little pass away. This difference 

 is determined not by the pabulum, but by the living material 

 which is destined to take this up, and which is concerned 

 in the formation of tissue. Some men and some animals 

 soon become fat upon a diet which to others would be 

 extremely low \ while certain individuals cannot be made fat, 

 although supplied with abundance of the choicest and 

 most fat-nourishing food. We must also bear in mind 

 that every tissue in the body does not share equally in 

 the increased nutrition, and although we often talk familiarly 

 of the increased or diminished nutrition of the body, we refer 

 for the most part to an increase or diminution of the adipose 

 tissue, and, though to a much less extent, of the muscular 

 tissue. At the same time we know that every tissue in the 

 body is nourished from the earliest period of its existence ; 

 but that of all the tissues when the organism is fully deve- 



