EwART — Variation : Germinal and Environmental. 363 



Even now, it is only necessary to interbreed half-bred animals, the offspring 

 of two varieties that have long lived apart, or cross-fertilize plants in which self- 

 fertilization has been the rule, in order to obtain an epidemic of variation, to 

 induce a more or less prolonged period of " sporting."* 



From the ofFspring of the half-breeds varying so much, it is evident that, 

 though they were all wonderfully like wild rabbits, the stability uf the wild rabbit 

 had been lost, that, as it is said of plants, crossing had broken down the " consti- 

 tution." But it maybe mentioned, the stability can soon be restored by engaging 

 in inter-breeding — which usually leads to exactly opposite results from inter- 

 crossing — and that even without close inter-breeding the "sporting" tendency 

 gradually wanes. 



Two of the offspring of the half-breeds (the grey- and the squirrel-coloured 

 ones) I crossed with pure white does, and with grey quarter-wild does. The 

 invariable result was a litter of mixed colours. 



By the crossings mentioned, and many others on record, I satisfied myself (1) 

 that under ordinary circumstances wild rabbits, bred with tame white bucks or 

 does, yielded grey rabbits ; (2) that half-wild rabbits, whether bred with each 

 other or with white rabbits, yielded offspring of three or more colours; (3) that the 

 offspring of two half-wild rabbits (even if grey), when bred with each otlier, or with 

 the grey offspring of a half-wild and a white rabbit, yielded young of several 

 colours ; and (4) that there is an intimate relation between the colour and [a) the 

 " wildness," (i^) the time maturity is reached, and (c) the rate of growth — white 

 individuals being tamer and sooner mature than grey. 



[h). Result of mating docs before and after the normal time. 



It is commonly believed by some {e.g. many gamekeepers and sportsmen) that 

 rabbits begin to breed when about six weeks old, while others assert that they only 

 reach maturity when six months old. At what age wild rabbits reach maturity I 

 have not determined, but I find tame and half-wild does living under favourable 

 conditions frequently mature during the fourteenth week, and have their first litter 

 during the eighteenth or nineteenth week, i.e.., before they are five months old. 

 Anticipating that four grey does (the offspring of a half-wild buck and a white doe) 

 born on the 8th February, 1899, would soon reach maturity, I placed one with an 

 Angora buck on the 10th June, i.e. when thirteen weeks old. Though the doe was 



* Were this power of " sporting" (varying) lost, a species would lose its power of adapting itself to 

 changes in the environment, and thus run the risk of extinction. Every pronounced change in the sm-round- 

 ings usually leads to a certain amount of mixing up (with its inevitable intercrossing) of forms which, in their 

 germ-plasm, if not in their outward characters, somewhat differ from each other. 



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