186 
Psyche 
[September 
and in many instances, specialization to tasks performed 
has caused the development of structural differences among 
the workers themselves. This is termed polymorphism. 
The differentiation of sexes is a form of polymorphism, 
and it would be admissible to speak of a male and a female 
caste, but that is as far as caste and polymorphism in any 
way homologous to that of insects has been carried in man. 
Since in a society which is based upon a grouping of small 
families 1 the production of offspring falls upon all, it 
follows that in order to maintain and perpetuate the society 
there cannot be present in it a large percentage of sterile 
individuals. Also, in that type of society, there cannot be 
any great degree of polymorphism, for the forming of 
numerous families implies the necessity for a wide range 
of possibility to mate. There is also the implication that 
any member of this society shall be able to carry on any 
function of the group. This may not seem evident at first 
glance, but human society is a conglomeration of numerous 
small societies, i. e., families, and because of the type of 
foetal development in the placental animals, and the period 
after birth during which the young are dependent, the 
maintenance of the family falls upon the adult members, 
and they cannot become so specialized that they cannot 
perform any one of the functions necessary for mainten- 
ance. Hence, if they must remain generalized with regard 
to the family, they must remain generalized with regard to 
society, which is but a group of families. (This refers only 
to morphological specialization) . Therefore it follows that 
the division of labor in the exploitation of the trophoporic 
field is, in man, brought about in a manner fundamentally 
different from that of the insects. It is not a specialization, 
in the biological sense, but is a development of one or more 
generalized abilities possessed in varying degrees by all 
members of the group. Therefore the laboring class, the 
iThe human family, no matter how large it may be, is, of course, 
a small one. This is evident when we consider that, at the utmost), 
one woman could bear only about 30 children, while a family of 
social insects may number well over a million individuals all produced 
by one female. 
