18 Proceedings. 



A change sufficient to constitute a new species might under certain rare conditions 

 have been brought about over a wide area without in-breeding ; but this must have been 

 41 1'are event. The evolution of the giraffe was instanced. It might have originated from 

 a herbivore not distinguished for height. A severe drought, making grasses and other 

 ground herbage scarce, would cause its ancestors to browse on leaves of trees. Those 

 with long necks, long fore limbs, or even with tongues an inch or two longer than others, 

 would survive, and the general mixing of these peculiarities would cause a marked change 

 in the structure of the animal. 



But most species must have originated in another way. An advantageous variation 

 would occur in a single individual, and this would be preserved and intensified by in- 

 breeding with others that would have the tendency to vary in the same direction. This 

 must have been the case where new organs originated, as the electric apparatus of certain 

 fishes, the luminous organ of the firefiy, &c. These organs are not present in the early 

 «mbyro, and are wholly absent in other species not far removed. The organ is probably 

 due to an individual accidentally developing it. 



These abnormalities would in nearly all cases be quickly obliterated by crossing 

 with others that had no trace of the peculiarity. In some cases, however, the individual 

 possessing the peculiarity would be, with one or two others of his kind, near relatives 

 probably, in some isolated ]3lace, and the in-breeding would intensify the abnormality 

 in some of the offspring. The favoured individuals would have some advantage over 

 others. It would be slight at first, as it is absurd to suppose that the complicated appa- 

 ratus, with its attendant nerves and blood-vessels, and the modification in the general 

 structure of the animal consequent on developing it, came into existence all at once. 

 Even if it did it would, imless such isolation and in-breeding occurred, be lost in a few 

 ■generations by general mixing. 



The efforts of plants to avoid self-fertilisation may be due to the advantage given 

 to an organism by variability in a changing environment. Cross-breeding with other 

 plants would give a more varied type, better fitted for the struggle for existence under 

 new conditions, as change of climate, difference of food, attacks of new enemies, &c. 

 These efforts have strengthened the belief in the injurious effects of close breeding ; 

 but in many cases the plants that are self-fertilised are of the most robust kinds, and 

 some of them were amongst the earliest to appear on the earth. If cross-breeding is of 

 such vital importance as is generally believed, such plants would have died out ages ago. 



Rabbits were introduced into New Zealand about fifty years since, and from a few 

 ■specimens the millions of fertile and vigorous animals all closely related have sprung. 



The sjDarrows now in the counti-y are another example of close in-breeding, as they 

 are all descended from a few pairs. Their fertility and general fitness for existence after 

 more than 150 generations of in-breeding are very marked. 



Again, the Maoris were descended from a few individuals who came to the country 

 in the traditional canoes. According to the general belief about in-breeding, idiocy, 

 hmacy, hysteria, &c., should be prevalent amongst them ; but they are not. 



The subject was one of economic importance, because it was easier to produce by 

 •artificial selection a desired type of plant or animal by in-breeding than by mixing with 

 non-related individuals. Further exhaustive experiments were needed, because if the 

 supposed ill effects of in-breeding did not exist, the belief was obstructing the production 

 of new varieties of plants and animals, and the error should be exposed. If in some 

 cases it produced bad effects, incpiiry was necessary to explain whj" in others theie was 

 no evil result whatever. 



Mr. A. H. Cockayne pointed out that one of the most striking and most successful 

 experiments in in- breeding had been made in New Zealand. He referred to the case 

 of the Corriedale variety of sheep. The object of the breeders of this sheep had been to 

 produce a general -utility animal — that is, one suitable both for yielding good mutton 

 and for growing a satisfactory class of wool. Pure-bred merino ewes and pure-bred 

 Lincoln rams had been crossed. Those of the offspring which promised best for the 

 desired purpose were crossed again, no restriction being made on the score of nearness 

 ■of relationship — in fact, the animals crossed were sometimes as closely related as it was 

 possible for them to be. Several experiments of this sort had been carried out, with 

 most satisfactory results. All the sheep bred true to type, and proved quite as hardy 

 iis could be desired. Mr. Cockayne also spoke of the valuable results obtained by in- 

 breeding in plants. The majority of new varieties of barley, sugar-beets, &c., and nearly 

 all modern strains of agricultural seeds, were kept true by almost continuous in-breeding. 

 When a departure from_ this practice had been ventured upon, and crossing had been 

 tried, the result of years of labour had been lost, and the breeders had been compelled 

 to begin again. 



The Chairman expressed the opinion that ]Mr. Poynton's jjaper was open to ciiti- 

 cism on more than one ground. The most important of these, perhaps, was that the 



