of Edinburgh, Session 1883-84. 
967 
The biological reader may well wonder at the insistance upon 
what is to him a commonplace ; but, like so many of the scientific 
commonplaces enlarged upon in the present analysis, it has been 
ignored by the vast majority of economic writers. It does not 
come within the study of processes of production on one hand, nor 
within that of social aggregates on the other ; the occupations of 
ploughman and weaver or joiner are alike productive — are all equal 
in the eye of the politician and before the law. To economists, 
whose preparatory studies included no biology, any insistance upon 
the wide difference of these occupations to the men performing 
them must needs seem mere nonsense, and the proposal to found 
practical action upon the observed results pure “sentiment.” 
But, without the slightest postulation of morals, it is a biological 
fact that, as “ function makes the organ,” it also shapes the 
organism, and modifies it either for evolution or for degeneration ; 
moreover, other things equal, determines its quantity of health and 
limits its length of life. Ploughmen and weavers, joiners or 
soldiers, then, are incipient castes, as surely as Brahmin and Pariah, 
queen, worker, and drone, are formed ones ] and the disadvantages 
of the division of labour, so slowly forced into prominence (as, little 
to the credit of biologists, they have been) through the sufferings of 
the many and the moral enthusiasm of an unscientific few, demand 
study and classification among the “Variations of Animals and 
Plants under Domestication.” 
§ 32. Modification by Environment , — Even when we study the 
ancestral environment separately as heredity, and the functional 
environment or occupation separately as function, besides leaving the 
social environment for a subsequent discussion, there remains a 
series of influences, those of the ordinary environment, which 
probably exceed any others in importance. Food, which alone 
determines whether the young bee is to be worker or queen, has a 
thoroughly well-marked influence upon men. The importance of 
the quality of the atmosphere is becoming recognised. So also 
with light : the gardener blanches his celery, the zoologist stops the 
development of the tadpole by withdrawing light, the sphygmo- 
graph shows how the pulse bounds at every gleam of sunshine, and 
the physiologist and physician are not hesitating to generalise and 
apply these results to the development of human life in towns. 
