966 
Proceedings of the Royal Society 
Beyond tlie primary economic differentiation involved by sex, all 
economic functions are at first united in eacb individual. As 
population increases, the advantage of numbers (tbe “ simple co- 
operation ” of economists) becomes felt ; then slight variations of 
individual and circumstance lead to the repeated performance of 
some one function by particular individuals, the efficiency and 
rapidity of its performance then alike improve, and the advantages 
of specialisation of function, or “ division of labour,” become 
obvious, and tend to be continued and perpetuated. This differ- 
entiation once set up, it continues as long as circumstances render 
it advantageous or possible, and the complicated co-operation of the 
ant-hill or the city alike arises. These familiar considerations show 
that the “ specialisation of functions ” in Formica and the ‘‘ divi- 
sion of labour ” in Homo are not merely ‘‘ analogies between man 
and nature ” — interesting only to those who care to trace such com 
parisons, — but are absolutely identical. 
§ 31. Result of Specialisation of Function upon Organism. — The 
differentiation of production leads then to the development of occu- 
pations, which, especially when perpetuated by heredity, are again 
seen to be of identical nature with those of the polymorphic indivi 
duals of the ant-hill. And all occupations are not directly con- 
cerned with production: some individuals specialise into the 
indirectly productive service of government; others leave productive 
operations on surrounding nature for the bodily care and service 
of their fellows ; others, again, become unoccupied ; and thus the 
three great classes of occujDations (^Classification of Statistics) are not 
simply analogous, but identical among bees, ants, or men, and are 
sometimes more differentiated in the former, sometimes in the 
latter. Just as the operations of heredity upon man and other 
organisms are not merely analogous but identical, so also are those 
of function. Division of labour has specialised the polymorphic 
castes of the ant-hill; so the same specialisation of function acts 
towards developing similar polymorphic changes among men. 
Every one is more or less conscious of this : it is never difficult 
to distinguish a soldier from a joiner, or a ploughman from a 
weaver; while the physician reaches almost incredible skill in 
eading the finer results of occupation on bodily structures, normal 
and pathological alike. 
