294 SCIENCE PROGRESS. 



perceive an advantage in the varieties of form, and an 

 adaptation of particular breeds to external circumstances." 

 He then gives numerous examples — the small active cattle 

 and horses which are found in mountainous countries, the 

 larger forms which flourish on fertile plains ; the various 

 breeds of the hog which are believed to hold "a particular 

 relation to the localities in which they are placed " ; the 

 change of a thick fleece into a thin coat when certain breeds 

 of sheep are transported to the tropics. " On considering 

 these and analogous phenomena, we can scarcely avoid con- 

 cluding that the variation of animals proceeds according to 

 certain laws, by which the structure is adapted to the 

 necessity of local circumstances." 



This statement looks at first sight very much like 

 natural selection. It is clear however that the writer held 

 a view similar to that which has been termed "self- 

 adaptation " by some modern writers, vie., that external 

 influences act on the oroanism in such a manner as to 

 evoke directly a favourable response. 



Examples of similar adaptation are then found among the 

 races of man. The skin of black races is considered to be 

 a protection against the effect of heat ; the native African 

 races can multiply in localities where a white population 

 cannot maintain its numbers, while negroes are unable to 

 establish themselves in northern latitudes. From these and 

 many other instances, it appears that "in mankind, as in 

 some other races, particular varieties are adapted by consti- 

 tution and physical peculiarities to particular local situations". 



The section finally concludes with the following para- 

 graph : "These remarks, if they are well founded, serve to 

 illustrate the doctrine of variation, or deviation, in the races 

 of animals in general, and they seem to lead us to the con- 

 clusion, that this is not merely an accidental phaenomenon, 

 but a part of the provision of nature for furnishing to each 

 region an appropriate stock of inhabitants, or for modifying 

 the structure and constitution of species, in such a way as 

 to produce races fitted for each mode and condition of 

 existence. A great part of this plan of local adaptation 

 appears to have been accomplished by the original modifi- 



