The Problem of Adaptation 27 



that its integrity is maintained. Most machines have no such 

 regulative power, although, in a sense, the fly-wheel of an 

 engine regulates the speed, and a water-bath, with a ther- 

 mostat, regulates itself to a fixed temperature ; but even this 

 comparison lacks one of the essential features of the regula- 

 tion seen in organisms, 'namely, in that the regulation does 

 not protect the machine from injury. It may be claimed, 

 however, that the safety valve of an engine does fulfil this 

 purpose, since it may prevent the engine from exploding. 

 Here, in fact, we do find better grounds for comparison, but, 

 when we take into account the relation of the regulations in 

 the organism to all the other properties of the organism, 

 we see that this comparison is not very significant. The 

 most essential difference between a machine and an organism 

 is the power of reproduction possessed by the latter, which is 

 absent in all machines. Here, however, we meet with a 

 somewhat paradoxical relation, since the reproductive power 

 of organisms cannot be looked upon as an adaptation for the 

 continuation of the individual, but rather for the preservation 

 of a series of individuals. Hence, in this respect also, we 

 cannot profitably compare the individual with a machine, but 

 if we make any comparison we should compare all the indi- 

 viduals that have come from a single one with a machine. 

 In this sense the power of reproduction is a sort of racial 

 regulation. A comparison of this sort is obviously empty of 

 real significance. 



The regenerative power of the organism, by means of 

 which it may replace a lost part, or by means of which a 

 piece may become a new whole, is also something not 

 present in machines. 



In using a machine for comparison we should not leave 

 out of sight the fact that machines are themselves the work 

 of organisms, and have been made for some purpose useful 

 to the organism. They may perform the same purpose for 

 which we would use our own hands, for they differ from 



