REPRODUCTION AND SEX 467 



Apart from hormones from the essential reproductive organs of 

 the female, there is evidence of others. The wall of the functioning 

 uterus is credited by some with a hormone that influences the 

 mammary glands and the production of milk. It is also affirmed 

 that the lactating milk gland produces a hormone that stimulates its 

 own activity! Very important, if confirmed, is the theory that the 

 placenta and the foetus produce moderative hormones that inhibit 

 milk secretion, which begins actively after birth, when the placental 

 and foetal inhibition has ceased. 



Very interesting also, but requiring confirmation, is the proba- 

 biHty that just as hormones from the mammalian mother pass 

 through the placenta into the developing young, so from unborn 

 young to mother there may be a passage of hormones which enable 

 her to make the most of her food. Thus the close ante-natal relation 

 of mother and offspring would be a symbiosis indeed. 



ILLUSTRATIONS OF THE PROBLEMS OF REPRODUCTION 



TELEGONY. — Telegony is a term coined by Weismann to describe 

 the influence of a previous sire on offspring (subsequently borne) 

 by the same mother to a different sire. Thus many dog-breeders 

 are convinced that if a pure-bred bitch has had pups to a mongrel, 

 her value is thereby greatly depreciated; the belief being that she 

 will not afterwards breed true when paired with dogs of good 

 breed. In other words, the influence of the mongrel (the previous 

 sire) is supposed to last, so that subsequent offspring by a pure-bred 

 sire are specifically affected. 



To cite a case, we read that "if a pointer bitch gets accidentally 

 served by a collie dog and produces a litter, the pups will be of 

 various types, some like the pointer, some like the collie, and some 

 a blend. And let that pointer bitch be afterwards served by a pure 

 pointer dog, the result will be a litter among which the collie type 

 can be unmistakably observed". 



It may seem strange that we should write as if there were any 

 doubt as to the occurrence of telegony, especially since a belief in 

 its reahty is translated into £ s. d. among breeders. It is said to 

 occur in horses, dogs, cats, sheep, cattle, pigs, rabbits, rats, mice, 

 and pigeons. There is no doubt as to the occasional occurrence of 

 pecuhar phenomena; the question is whether they can be inter- 

 preted as evidence of telegony. Thus there is an occasional occurrence 

 of hark-backs or reversions, and there is often a rehabilitation of 

 MendeUan recessives which have remained latent for generations. 



But when such things happen and are not understood it is natural 

 that the breeder should lay the blame on some chance crossing. 

 Especially natural will this be when the chance crossing was fol- 



