678 EEPORT — 1901. 



The Direct Action of the Environment and Use-Inheritance as Causes 



of Variation. 



Of the doctrine of the transmission of acquired characters, still so often the 

 subject of discussion, I need say little more than that I have failed to discover 

 any evidence in its favour. Writing in 1S76, Darwin says, ' In my opinion the 

 "reatest error which I have committed has been not allowing sufficient weight to 

 the direct action of the environment, i.e., food, climate, &c., independently^ of 

 natural selection.' ^ Darwin not only in his later years reverted to the teaching 

 of Buffon, but, in as far as he continued to believe in the ' inherited effects of use 

 and disuse,' he adopted the views of Erasmus Darwin and Lamarck. While 

 admitting that the direct action of the environment on the soma and use- 

 inheritance are indirect — it may be potent — causes of variation, I do not believe 

 there is any trustworthy evidence in support of the view that definite somatic 

 variations are ever transmitted. 



Telegony as a Cause of Variation, 



The belief in telegony is less deserving of consideration than the doctrine of 



the transmission of acquired characters. Nevertheless I perhaps ought to refer 



to it at greater length, not so much because of its scientific importance, but 



because it interests all sorts and conditions of men in many diiierent parts of the 



world. Telegony (' infection of the germ ' of older writers) means that not only 



the immediate parents but also the previous mates (if any) contribute to the 



characters of the offspring ; that, e./y., a mare which had produced foals to, say, 



' Ladas' and ' Persimmon' might thereafter give birth to a foal by ' Flying Fox,' 



to which ' Ladas ' and ' Persimmon,' as well as the actual sire, contributed some 



of their characteristics. Many even think a sire may transmit definite structural 



characters from one mate to another. If there is such a thing as telegony, if it is 



possible to blend, without the risks of intercrossing, the characteristics of several 



individuals or varieties, progressive development would be greatly accelerated. 



Though the doctrine of ' infection ' has probably long formed part of the breeder's 



creed, it received but little attention from men of science until in 1820 Lord 



Morton communicated a case of infection to tlie Pioyal Society, which in due time 



was published in the ' Philosophical Transactions.' In this the most credible and best 



authenticated of all the cases of telegony on record a chestnut mare, after rearing a 



quagga hybrid, produced to a black Arabian horse three foals of a peculiar bay 



colour, one of them (a filly) showing more stripes than the quagga hybrid, and, 



accoi-ding to the stud groom in charge of ' the colts,' characterised by a mane 



'which from the first "was short, stiff, and upright.'- Darwin, after fully 



considering Lord IMorton's case, came to the conclusion that the chestnut mare 



had been infected, and this case along with others led him to believe that the 



first male influenced ' the progeny subsequently borne by the mother to other 



males.' ^ If the upright zebra-like mane in one of the pure-bred colts and the 



markings on all three were the result of the chestnut mare having been first 



mated with a quagga, there is undoubtedly such a thing as telegony, and the 



presumption is that other mares first mated with a quagga or zebra and then with 



a black Arabian would give birth to striped ofispring with a stiff if not quite 



upright mane. The evidence that from the first the mane of the filly was short, 



stifl', and upright is most unsatisfactory. It consists of an allegation by a stud 



groom. That the mane was upright, as in the quagga and zebra, is « ;5)wr(' 



improbable, (T) because the mane of the quagga hybrid instead of being short and 



stifi' was long and lank enough to arch to one side of the neck ; (2) because the 



mane of zebra hybrids throughout the greater part of the year is so long that 



it falls to one or it may be both sides of the neck ; and (3) because in the Equidee 



' Life and Leitei's : Letter to Moritz Wagner. 



= Phil. Trans., 18207p. 21. 



' Animals and Plants, v6l. ii. pp. 435, i36. 



