38 NUTRITION DEPENDS ON THE 



Exercise and labor cause a diminution in the quantity 

 of the menstrual discharge ; and when it is suppressed 

 in consequence of disease, the vegetative life is mani- 

 fested in a morbid production of fat. When the equi- 

 librium between the vegetative and nervous life is dis- 

 turbed in the male, when, as in eunuchs, the intensity 

 of the latter is diminished, the predominance of the 

 former is shown in the same form, in an increased 

 deposit of fat. 



VIII. If we hold, that increase of mass in the ani- 

 mal body, the development of its organs, and the supply 

 of waste, that all this is dependent on the blood, that 

 is, on the ingredients of the blood, then only those sub- 

 stances can properly be called nutritious, or considered 

 as food, which are capable of conversion into blood. 

 To determine, therefore, what substances are capable 

 of affording nourishment, it is only necessary to ascer- 

 tain the composition of the food, and to compare it with 

 that of the ingredients of the blood. 



Two substances require especial consideration as the 

 chief ingredients of the blood ; one of these separates 

 immediately from the blood when withdrawn from the 

 circulation. It is well known that in this case blood 

 coagulates, and separates into a yellowish liquid, the 

 serum of the blood, and a gelatinous mass, which adheres 

 to a rod or stick, in soft, elastic fibres, when coagulating 

 blood is briskly stirred. This is the fibrine of the blood, 

 which is identical in all its properties with muscular 

 fibre, when the latter is purified from all foreign matters. 



