280 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [VI, III

looms up the Charybdis of the likelihood that the analysis will reveal so many
genetic factors interacting with each other as to make the synthesis of the problem
in its practical application almost an impossibility. An adequate reply to the
opening questions of this paper demands the discussion of this point.

To those who have time to reflect, the practical outcome of the work of the
plant-geneticist is little short of amazing. For many crops he has managed to
make two blades grow where none could grow before. We, animal geneticists,
have good cause for envy, and it is well that we should point out that this cause
lies not merely in the greater rate with which one generation of agricultural plants
succeeds another and the large populations which can be conveniently raised, but
also in the fact that the productivity of a plant is, as a rule, infinitely more easy
to measure and to assess than is the productivity of an animal.

The problem of an increase in the productivity of our live stock—and the
maintenance of that increase—is not so simple as, say, the problem of an increased
yield in maize. Let me refer to the work of Winter [3], which has been recently
the subject of some discussion. To quote 'Student' [4], Winter 'succeeded, by
continuous mass selection, in producing two races of maize one of which has more
than twice, and the other less than one-third, the normal oil-content'. ' The
movements of the means were, respectively, more than twelve and seven times the
" inherent " standard deviation.' ' Student' estimates that at least 100 to 300
factors would be needed and considers that the actual number runs into thousands.
Dealing with this point, Dr. Fisher [5] states that the experiment (which ran for
twenty-eight years) is a direct demonstration that selection has the exact effects
that selectionists have ascribed to it.

Can we do likewise if we breed our cattle upon the same principle of selection ?
There, is no doubt that selection can greatly increase the productivity of scrub
stock, but as the productivity of improved stock rises so does the rate of improve-
ment decrease. The progress becomes so slow relative to the passage of years
that we must now perforce accustom our ears to the astonishing slogan of certain
advisers of our farmers that it is useless to use a bull that is out of a high-producing
cow, a statement based on the fact that certain bulls of such breeding do not fulfil
the expectations of the owner. Nevertheless the occurrence of such animals does
fulfil the expectations of the geneticist.

It is curious that some of those of our practical advisers who most decry the
simple selection embodied in the ancient rule of ' mate the best to the best' do
themselves advise merely an elaboration of simple selection. So keen are these
people on their slogan of the ' progeny test' as the salvation of the British dairy
industry, that they go out of their way to decry past methods of selection—com-
bined or not with pedigree. They quite ignore the point that the progeny test is
merely the logical refinement of existing methods of selection.