time: the refreshing river 



Lastly, as in private duty bound, I come to the subject of bio- 

 chemistry. To sociologists the subject of human nutrition cannot fail 

 to be of interest, and it is biochemistry which shows us what a properly- 

 balanced and adequate diet should contain, and how any given diet 

 falls short of these requirements. We shall doubtless all be familiar 

 with the recent work of Orr^ in which the nutritional aspects of the 

 class-stratification of the social system in which we live, are graphically 

 plotted. An optimum diet is defined as a diet to which nothing need 

 be added to ensure a better degree of health and well-being. In England 

 we find that about half of the entire population fall below this level, 

 and clearly this must mean a great deal more than half of the working- 

 class. In the lowest group of all, containing lo per cent of the popula- 

 tion, the diet is deficient in every single constituent, minerals, vitamins, 

 organic substances, etc., and it is significant that no less than 25 per 

 cent of the children of the country fall into this group, precisely 

 because the larger number of children in a family, the more tendency 

 tliere is for the family to come into the lowest group, even if the 

 wage-earner is well paid relatively, since the groups are reckoned on 

 a per capita basis of weekly income. In the disputes of recent times 

 about the absolute minimum upon which a family can support life, 

 we have seen biochemistry, brought into the limelight by august 

 public bodies whose good intentions and would-be generosity cannot 

 be questioned, become a subject as controversial as geology once 

 was when the episcopate was a more powerful (or less diplomatic) 

 intellectual force than it is now. Whatever the outcome may be, the 

 sociologist must always take into account, as one of his essential 

 base-lines, the knowledge concerning the chemical constitution of 

 man and its maintenance, which it is the business of the biochemist to 

 provide. 



Boundaries of Social Theory. 



In conclusion, to restate the thesis of the present paper would be 

 to say that biology, like biochemistry and biophysics, is an unescapable 

 datum for the sociologist. It gives the limits within which the answer 

 must fall, and not the answer itself. Like the crystal physicist who 

 can say of the proposed chemical formula of a substance that whatever 

 the true one is it cannot be that one, without being able to say what 

 the true one is; so the biologist can lay down numerous boundaries 

 which no social theory can expect to transgress. Whatever the details 



^ J. B. Orr, Foodf Health and Income (London, 1936). 



176 



