DIVISION OF LABOUR 25 



and each by his training, education, even by his 

 capabilities in hands, feet, eyes, &c., succeeds best 

 in the trade or profession for which he is best suited. 

 A false selection is followed sooner or later by failure, 

 or at least by indifferent success, just as a glandular 

 cell would form but a feeble protective agent, or a 

 skeleton cell an ineffective contractile one. Further, 

 a society is successful, a nation prosperous, only if 

 there be harmonious co-operation between the units 

 composing it, when they all, in a word, work for the 

 common good ; so, too, every cell in the healthy 

 body must play its appropriate part in the general 

 economy, and take its due share in the work carried 

 on by the body as a whole. Should it fail to do so, 

 disease in the organism results sooner or later. A 

 strike or a revolution is a disastrous phase in the 

 history of a society, it is equally disastrous in that 

 of a cellular community. 



As a result of this rapid survey of organic nature 

 we have seen that we may distinguish successively 

 higher grades of organisation in both plants and 

 animals, beginning with unicellular types and pass- 

 ing through multicellular, almost undifferentiated p r o- 

 forms to such as show complete differentiation of 

 structure and division of labour. We have also tiation 

 seen that every plant and every animal starts life as divid 

 a single cell be it oosperm or zoospore, as in the 

 majority of plants, or oosperm only, as in the great 

 majority of animals. Obviously, the same general 

 advance from the unicellular to the multicellular and 

 from that to the completely differentiated condition 

 must be met with in the life-history of every higher 

 organism. Look, for example, at the early stages 

 in the life-history of the frog. The oosperm is a 

 unicellular organism just like the oosperm of 



