THE SCIENCE OF STOCK-BREEDING. 
731 
them out of Nature’s course, and they become dependent in a great 
measure on his attention for their survival. So that, being again left 
comparatively to themselves, Nature commences culling off the 
abnormal developments induced by man’s treatment back on the lines 
of the original hardy unimproved prototype. For example, in animals 
that have beeu bred specially for early maturity and enormous meat 
production, it is found under the forcing influence of our soil and climate 
that the most highly improved in this respect are soon culled off, if man 
does not interfere, through the female either breeding too early or, 
when they do reach a fit age, through being in too high condition to 
breed at all ; consequently only the least highly improved in that specific 
line — those most resembling the original unimproved breed — are per- 
mitted to survive or propagate. In the same way if milking propensities 
are abnormally developed, it is found that after parturition, when left 
without man’s care, from the great How of milk the milk vessels often 
get inflamed and swell up so that the young one, not being able to 
draw it off, gets weak and probably dies, while the dam is not likely 
ever to rear her young on account of permanent injury to these organs. 
In wool production abnormal development may frequently be seen 
when the wool grows over the face, covering the eyes of the sheep, and 
causing it to be unfit to take care of itself. Many like illustrations 
might be given. In matters appertaining to general health, when man 
puts more stock on a given area than Nature would permit, she rights 
it herself by killing off all the weakly constitutioned and predisposed to 
disease, by what we choose to call diseases and pests. This is Nature’s 
mode of readjusting the balance in order to preserve a living remnant 
fitted to survive some of Nature’s many modes of culling. When pasture 
is closely stocked up by any one class of stock, sanitary arrangements 
must he made for keeping it fresh, clean, and untainted by disease, 
measures being at the same time taken for killing off and burying 
or otherwise finally disposing of all diseased, delicate, and unprofitable 
“ wasters,” so that they may not disseminate disease among others. 
On dirty, badly managed pasture the constitutional tone gets low and 
predisposes stock to disease. Nature puts a stop to unnatural 
developments and restores the constitutional balance in her own way 
when man is wanting in knowdedge or energy to do so. Proper 
sanitary arrangements cannot be made in enormously large paddocks, 
nor so well on very large holdings as on moderately small ones. 
It is the opinion of men of practical experience, who have had 
opportunities of judging, that the average quality of our flocks and 
herds generally is equal, and in some classes superior, to any in the 
world; and this ought to be so, considering that from the commence- 
ment of breeding in Australia there has been the power of using the 
most highly improved imported animals. From a national point of 
view what has to he considered is not the present immediate demand 
for certain crosses or mixtures of improved breeds, but the effects on 
the future of our stock of breaking down the prepotency of highly 
improved breeds, while not establishing or preserving types with fixed 
characteristics suitable to their surroundings. It would be a national 
benefit, were it practicable, to procure the evolution with prepotency 
of valuable new types adapted to our special conditions of climate and 
markets, but this cannot he done by breaking down highly prepotent 
breeds in experimental crossing. It may be done by persistently 
