1 June, 1899. ] QUEENSLAND AGRICULTURAL JOURNAL. : 435 
The differentiation has become more and more complete, when those young 
animals, in whom a perfect amalgamation of the qualities of father and 
mother and a normal formation of the reproductive organs, had not taken place, 
did not survive. 
The breeding of domestic animals for the purpose of obtaining more 
desirable animals thus chiefly consists in producing new varieties of the same 
species. Such new varieties should, firstly, possess the qualities we desire in a 
higher degree of perfection, and, secondly, transfer them wholly and perfectly 
to their offspring. J+ is clear that a breed of apparently good qualities is really 
of no value unless we can rely upon its perfections reappearing and becoming 
intensified in many generations to come. It is of interest to us to ascertain 
‘the reasons why some breeds of animals are so very variable—the horse and the 
dog, for instance—and others —the zebra, the wolf, the fox—are so tenaciously 
uniform in retaining the qualities of their ancestors. Considering the great 
difficulty of learning something definite wbout the natural laws according to 
which are regulated, on the one hand, the variability of our common domestic 
breeds, on the other that tenacity peculiar to wild racés and to highly cultivated 
breeds, it is a remarkable fact that the most experienced and successtul breeders 
of these and former times have entertained the notion that their results in 
breeding were not owing to fortuitous circumstances, or accidents, but that 
they were regulated by certain laws or necessities in the household of Nature. 
The most important ones of these laws had been agreed to, and were accepted 
by almost all successful breeders, long before they were eyentually expressed in 
v scientific form, and handed to the world in the works of Darwin, Wallace, 
and other scientists. It is admitted by almost everyone acquainted with the 
phenomena in breeding, that the facts collected by Darwin in different parts of 
the globe during a period of about twenty years, have furnished the strongest 
scientific corroboration of the opinions held by the most successful breeders for 
more than 100 years. ; . 
I shall briefly describe Darwin’s theory, and name a few facts which might 
‘illustrate the laws which, according to Darwin, haye caused the origin of species, 
and which have still an effect upon the formation of any new variety that we 
may desire to establish. 
Darwin believes that all animals and plants derive their descent from a few, 
perhaps only slight, organisms, and he has tried to show how the offspring of 
these comparatively imperfect beings have gradually developed into more pertect 
forms, and why the animals of the present day show so great a variety in form, 
qualities, temperament, and habits, &c. Darwin’s theory 1s hardly calculated to 
assert itself in the minds of those who are only slightly acquainted with natural 
history and with the methods employed by naturalists in getting at results, and 
in the minds of those who entertain a strong reverence for the traditional. Yet 
there is no getting over facts, and, as Darwin has discovered and explained a 
great number of them, we are justified in accepting any reasonable explanation. 
of them until a better one is given. ; ‘ : 
Darwin has shown that the development of low organisms into higher forms 
is chiefly due to— 
1. Influences, telluric and climatic, that had a modifying effect on 
the living organisms. 
To the struggle for existence, and the survival of the fittest. 
. Through natural selection, frequently carried on unconsciously. 
Though certain habits and inclinations being strongly developea 
and transmitted to after generations. 
If the surface of the earth had remained in its primitive condition, the 
forms of the animal and vegetable organisms then existing would be the same 
now as they were in the beginning, and in fact a good many of them are still 
preserved. Their variation would then have been comparatively slight, and 
their types would soon have become fixed. Changes in the surface of the 
earth, whether slow or violent, must have occasioned a great destruction of 
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