44 Home Economics and Biological Cheiinstry [Sept. 



introduced at the N. Y. Teachers' College, and which, I believe, is 

 partictilarly well adapted for the Instruction of all whose interests 

 incltide an understanding of the principles of general nutrition and 

 dietetics, or any other chemical phase of biology. 



In the course to which I alliide, we place at the foundation of 

 our experiments and discussions, the chemistry of typical cells as 

 the Units of living structure and the essential factors in biological 

 dynamics. Every organism consists primarily of one or more cells. 

 The higher organisms consist not only of cells but contain 

 also much important material that is produced by and in their 

 cells, but which is extracellular in location. Life is so intimately 

 associated with intracellular chemical transformations of energy 

 that it seems to be dependent on, and apparently is an expression 

 of, such intracellular changes. Many of the extracellular changes 

 in organisms are of minor importance in the maintenance of life. 



Chemical transformations of energy always involve chemical 

 alterations of substances, i. e., the production of one group of 

 substances from another. Cells consist of mixtures of complex 

 substances, which collectively, during the life of the cells contain- 

 ing them, continuously undergo life-maintaining chemical and 

 physical alterations. Such changes involve the consumption of use- 

 ful and, to some extent, of necessary intracellular substances, with 

 an attendant production of certain simpler Compounds ("waste 

 products") that are of no use to the cells (catabolism). Accumu- 

 lation of waste produces in a cell interferes there mechanically 

 and chemically with further beneficial transformations. Waste 

 products are promptly ejected from normal cells. 



Cells cannot retain their structural integrity, and are also un- 

 able to maintain their dynamic capacity, unless the life-giving in- 

 tracellular processes of consumption and excretion (catabolism) 

 are accompanied or followed by compensatory intracellular proc- 

 esses of repair, or direct replacement, or both (anabolism). This 

 general conception furnishes the key to the whole subject of physio- 

 logical chemistry. It carries us to the foundation of chemical 

 biology. It emphasizes the cardinal fact that the utilization, re- 

 moval and replacement of materials by an organism are expressions 

 of its collective cellular requirements and peculiarities. 



