GERMINAL SELECTION. 65 



erred when they ascribed hereditary effects to the se- 

 lection-processes which are enacted among the parts 

 of the body (Wilhelm Roux) and which are rightly 

 regarded as the results of functioning. And they did 

 this, moreover, as they themselves admit, not because 

 the facts of heredity directly and unmistakably re- 

 quired it, but because they saw no other possibility of 

 explaining many phenomena of transformation. I am 

 fain to relinquish myself to the hope that now after 

 another explanation has been found, a reconciliation 

 and unification of the hostile views is not so very 

 distant, and that then, we can continue our work 

 together on the newly laid foundations. 



That the application of the Malthusian principle was 

 thoroughly justified is now clear. The entire process 

 of the development of living forms is guided by this 

 principle. The struggle for existence, videlicet, for 

 food and propagation, takes place at all the stages 

 of life between all orders of living units from the 

 biophores recently disclosed upwards to the elements 

 that are accessible to direct observation, to the cells, 

 and still higher up, to individuals and colonies. Con- 

 sequently, in all the divers orders of biological units 

 lying between the two extremes of biophores and 

 colonies, the modifications must be controlled by se- 

 lective processes ; therefore, these govern every change 

 of living forms no matter what its significance, and 

 bring it about that the latter fit their conditions of 

 life as wax does the mould ; and the various stages of 

 these processes, as enacted between the divers orders 

 of biological units, in all organisms not absolutely 

 simple, are involved in incessant and mutual inter- 

 action. The three principal stages of selection, that of 



