HEREDITY 201 



changes in the skin or in the muscles, in the bones 

 and cartilages, or accumulate in the blood products 

 highly necessary, as sugar, having power to retard 

 or accelerate their consumption." 



This paragraph will facilitate our comprehension 

 of the theory of heredity, and remind us of the 

 great prominence the nervous system has in the 

 action of nutrition, not of the tissues, but of the 

 cells themselves. 



In the glands the nerve-endings reach the 

 glandular cells, and have a direct influence upon 

 the process of secretion; they can, as Charrin 

 states, excite hunger or infect with poison according 

 to the state of the nerve apparatus : thus joy and 

 well-being give a sound feeling of life, happiness, 

 and health; on the contrary, serious mental dis- 

 appointments, the worries and upsets of existence, 

 in altering the normal state of the nutritive changes 

 in the cells and the glandular secretions, poison 

 life and predispose to or aggravate disease. 



Observe the curious instances taken from the 

 excellent work of Dr Marfau, 1 which explain the 

 rdle of the nervous system, and which we quote 

 also to assist the comprehension of the theory of 

 heredity : 



" The wife of a rich merchant married her 



1 Bouchard, Pathologie generate, "Fatigue et surmenage," p. 509. 



