PREADAMITE MAN. 135 



hypothesis of Lamarck be assumed in its entirety, whereby 

 a multitude of organised forms will have sprung up, their 

 character mostly determined by external conditions, then it is 

 reasonable to assume the permanence, in the highest degree, 

 of those forms which are most adapted to the conditions. 

 Some would have a greater degree of viability, or power of 

 living, than the others ; and thus, time being given, the forms 

 vitable in the lowest degree would die out. Amongst the 

 external conditions upon which the permanence of a species 

 may depend, the presence of other species and the correlation 

 between them must not be left out of account. Probably, 

 Mr. Darwin remarks, there does not exist any one organised 

 species, whether animal or vegetable, that is not in some 

 measure correlated with all other species, though the links of 

 correlation are not often manifest. In the course of many 

 ages the vegetable characteristics of several regions adequately 

 studied are known to have undergone a radical change, of 

 which an example has been already furnished when treating 

 of the Danish bog-formations. If a naturalist were now asked 

 to explain the nature of the conditions through the operation 

 of which the growth of Scotch firs declined in Denmark, then 

 wholly ceased, forests of scrub-oak taking their place ; why, 

 at some subsequent epoch, the latter gave place to beech forests 

 the naturalist questioned on this matter would be unable to 

 explain. He would nevertheless be able to illustrate by way 

 of parallelism. Correlative dependencies still operating are 

 ready to proclaim the general truth to all who seek it. 



Thus the flourishing of the Scotch fir in Scotland is seen 

 to be determined to so great an extent by the presence of 

 cattle as to warrant the naturalist in assuming that if Scotch 

 cattle were exterminated, the natural growth of Scotch fir, by 

 which is meant growth without man's intervention, would 

 cease. The explanation is consistent enough. When the firs 

 grow, heather grows too, and so thickly that, if not browsed 

 down, the heather suffocates the young fir-trees. Here the 



