OX ID A TION AND NUTRITION. 3 7 



2. Are oxidation and nutrition always taking place in 

 each particle of the human body during life ? There are 

 tissues in the body which are never nourished and never 

 oxidised after their formation is complete. Were it not 

 stated in two distinct places, I should have doubted if the 

 remark was intended. I cannot conceive a statement less 

 justified by what is known of the changes going on in living 

 beings than the assertion that " oxidation and nutrition are 

 always taking place in each particle of the human body 

 during life." Every single texture of every living thing 

 consists of matter in two distinct states, in which changes 

 of a totally different kind are going on. No one can 

 obtain from any organism a single piece of structure of any 

 kind measuring ^^th of an inch in every direction which 

 exhibits uniformity of structure and composition, or consists 

 of particles all undergoing the same sort of changes. Take 

 even a single epithelial cell : its outer part is dry, and 

 hard, and passive, and dead ; its innermost portion is soft, 

 and diffluent, and active, and living. The latter alone is 

 the seat of vital actions. 



But what is meant by a " particle " of the human body ? 

 If the tissues were composed of matter exhibiting the same 

 characters throughout, a "particle" might mean a small 

 piece, of no very great size or definite form ; if of a number 

 of bodies like stones or pebbles, or bricks as in a wall, 

 "particle" might mean one of these, and each might be 

 said to consist of smaller " particles ; " but the tissues are 

 not so constituted. If by "particle" is meant what is 

 usually called "cell," such particle is not of the same 

 character throughout, and is certainly not always undergoing 

 the processes of oxidation or nutrition. If by "particle" 



