68 ESSAYS OF A BIOLOGIST 



constitution, exposed to the environmental forces of 

 the same planet, had reacted in similar ways, develop- 

 ing along parallel lines, and arriving at similar types 

 of organization as end-result. Thus it might reason- 

 ably be supposed that we should find the same general 

 organization and mode of development in one type 

 of organism as in another, in human society as in a 

 vertebrate. 



On these bases, Spencer and his followers drew 

 elaborate comparisons of the two, and apparently 

 believed that they were reaching the same degree 

 of accuracy as that found in comparative anatomy 

 when they compared the circulatory system of a 

 mammal with the transport facilities of a State, or 

 drew parallels between the brain and the cabinet. 



It was speedily seen, however, that such general- 

 izations were so broad and vague as not to be of much 

 service : that the resemblances were in fact often 

 no more than symbolical or metaphorical, instead 

 of being based upon detailed similarity of constitu- 

 tion or of evolutionary development. With this, 

 evolutionary theorizing on sociological matters fell 

 somewhat into disrepute. The earlier jubilant 

 certainty gave place to later doubt ; and the half- 

 century whose beginnings had roused Haeckel and 

 Herbert Spencer to their imaginative flights closed 

 suitably enough with that remarkable document, T. H. 

 Huxley's Romanes Lecture, in which the greatest 

 protagonist of Darwinism confesses to seeing be- 



