768 BEPOET— 1889. 



transmission. Professor His, of Leipzig, doubts its validity. Professor Weismann 

 says that there is no proof of it. Mr. Alfred Russel Wallace, in his most recent 

 work,' considers that the direct action of the environment, even if we admit that 

 its effects on the individual are transmitted by inheritance, are so small in com- 

 parison with the amount of spontaneous variation of every part of the organism 

 that they must be quite overshadowed by the latter. Whatever other causes, he 

 says, have been at work, natural selection is supreme to an extent which even 

 Darwin himself hesitated to claim for it. 



There is thus a conflict of opinion amongst the authorities who have given 

 probably the most thought to the consideration of this question. It may appear, 

 therefore, to be both rash and presumptuous on my part to offer an opinion on this 

 subject. I should, indeed, have been slow to do so had I not thought that there 

 were some aspects of the question which seemed not to have been sufficiently 

 considered in its discussion. 



In the first place, I would, however, express my agreement with much that has 

 been said by Professor Weismann on the want of sufficient evidence to justify the 

 statement that a mutilation which has affected a parent can be transmitted to the 

 offspring. It is, I suppose, within the range of knowledge of most of us that 

 children born of parents who have lost an eye, an arm, or a leg come into the 

 world with the full complement of eyes and limbs. The mutilation of the parent 

 has not affected the offspring ; and one would, indeed, scarcely expect to find that 

 such gross visible losses of parts as take place when a limb is removed by an 

 accident or a surgical operation should be repeated in the offspring. But a similar 

 remark is also applicable to such minor mutilations as scars, of the transmission of 

 which to the offspring, though it has been stoutly contended for by some, yet seems 

 not to be supported by sufficiently definite instances 



I should search for illustrations of the transmission of somatogenic characters 

 in the more subtle processes which affect living organisms, rather than those which 

 are produced by violence and accident. I shall take as my example certain facts 

 which are well known to those engaged in the breeding of farm-stock or of other 

 animals that are of utility to or are specially cultivated by man. 



I do not refer to the influence on the offspring of impressions made on the senses 

 and nervous system of the mother, the first statement of the effects of which we 

 find in the book of Genesis, where Jacob set peeled rods before the flocks in order 

 to influence the colour and markings of their young ; though I may state that I 

 have heard agriculturists relate instances from their own experience which they 

 regarded as bearing out the view that impressions acting through the mother do 

 influence her offspring. But I refer to what is an axiom with those who breed any 

 particular kind of stock, that to keep the strain pure, there must be no admixture 

 with stock of another blood. For example, if a shorthorned cow has a calf by a 

 Highland sire, that calf, of course, exhibits characters which are those of both its 

 parents. But future calves which the same cow may have when their sires have 

 been of the shorthorned blood, may, in addition to shorthorn characters, have others 

 which are not shorthorned but Highland. The most noteworthy instance of this 

 transmission of characters acqmred from one sire through the same mother to her 

 offspring by other sires is that given in the often-quoted experiment by a former 

 Lord Morton.'' An Arabian mare in his possession produced a hybrid the sire of 

 which was a quagga, and the young one was marked by zebra-like stripes. But 

 the same Arabian had subsequently two foals, the sire of which was an Arab horse, 

 and these also showed some zebra-like markings. How, then, did these markings 

 characteristic of a very different animal arise in these foals, both parents of which 

 were Arabians ? I can imagine it being said that this was a case of reversion 

 to a veiy remote striped ancestor, common alike to the horse and the quagga. 

 But, to my mind, no such far-fetched and hypothetical explanation is neces- 

 sary. The cause of the appearance of the stripes seems to me to be much 



' Darwinism, p. 443 ; London, 1889. 

 . - Philosophical Transactions, 1881 ; also Darwin's Animals and Plants under 

 JOomestieation, first ed. vol. i. p. 403, 1868. 



