138 Biochemical Proceedings, Hygienic Congress [Sept. 



malacia and similar conditions. An important factor is the degree 

 to which overproduction takes place, a factor involved also in im- 

 munity and, in fact, in all tissue repair. 



Other disturbances which may be said to involve quantitative dis- 

 turbance in bone growth, — the rate of growth, — rather than dis- 

 turbances in the qualitative character of the bone produced, are the 

 various types of dwarfism. In some of these the failure to grow 

 seems to depend on an absence of the " growing tendency " on the 

 part of the bones; in others, some disturbance in the supply of 

 lime salts available for bone growth seems to be at fault. 



The role of proteins in growth 



LAFAYETTE B. MENDEL 



Some of the views held in the past regarding the interrelation of 

 the food supply and growth are no longer tenable. Growth has 

 often been associated in a causal way with the relative abundance of 

 protein in diet. The parallelism between the protein content of the 

 milk of various species and rate of growth may, in the familiär cases 

 be an example of correlation rather than of causation. Recent in- 

 vestigations have shown that the assumed association of growth 

 with high protein intake is not confirmed by the evidence at band. 



Growth is a function of the cells. This inherent capacity ap- 

 parently cannot be exaggerated by feeding ; but growth can be held 

 in abeyance by various conditions. These include inadequacy of the 

 food supply in respect to both quantity and quality of the nutrients. 

 Attention must be directed to the chemical as well as the energetic 

 aspects of the problems involved. In the past physiologists have 

 largely disregarded the relative values of the individual members of 

 different groups of food substances in nutrition, owing to an igno- 

 rance of the chemical characteristics of the individuals. 



In considering the uses of protein in the organism, the distinc- 

 tion between the requirement for maintenance and that for growth 

 must be clearly kept in mind. The development of a successful 

 method of investigation by Osborne and Mendel has made it easy to 

 approach some of the problems experimentally. The method was 

 explained in detail. Normal rate of growth has been induced in 



