LECTURE XIV. 403 



can easily refute such an assertion, and prove that in a herd of 

 wolves, for instance, the individual difference is as great as in 

 a flock of sheep propagated by inbreeding. If the assertion 

 of perfect resemblance were well founded, no collector would 

 take the trouble to make a selection. There obtains, there- 

 fore, an individuahty in the whole animal kingdom just as in 

 mankind and the domestic animals, and if, in common life, we 

 pay no attention to it, it is because we see no use in so doing. 



The transmission of individual characters, which distinguish 

 not merely the species, but also the family and the individual, 

 is thus one of those facts which must have a general influence 

 on the forms of the animal kingdom, and it is the transmission 

 of peculiarities distinguishing the individual which has become 

 such a powerful lever in improving the breeds of our domestic 

 animals. 



Virchow has recently, in an excellent treatise, raised the 

 question whether the sum of characters transmitted is always 

 the same ? As was expected, he arrived at the conclusion 

 that this neither is nor can be the case, for the simple reason, 

 that a change of the established family-type would thereby be 

 rendered impossible. The possibility of any alteration rests 

 upon this : that the hereditariness embraces an undeterminable 

 sphere of characters, the extent of which can only be learned 

 by experience. It is frequently impossible to predict whether 

 this or that animal, possessing otherwise some excellent qua- 

 lities, may not transmit to its progeny some germ of disease, 

 which only breaks out at a later period, while apparently 

 inferior animals produce a stock suitable for the purpose of the 



breeder. 



I have in a preceding lecture explained that the word '^race" 

 in the sense in which it is used, cannot be separated from the 

 notion " species," since the constancy in the transmission of 

 characters, the resistance against external influences, and the 

 adaptation to surrounding media, are frequently as great in races 

 as in the so-called species, and may be traced back to remote 

 antiquity, as is done in species. The term "race" expresses, 

 perhaps, only a theological idea. Applied to domestic animals 

 it is often used as equivalent to species, as it was known that 



dd2 



