(2 of 2)
The records of racehorses have been kept better than the records of man or any other animal, and their study has been the most thorough. A statistical analysis of speeds over a period of 150 years, shows that selectively breeding swift horses has progressively produced swifter ones. Man o' War, sire of the 1929 Kentucky Derby winner (TIME, May 27), was the best racehorse that ever lived. Interesting is the observation that in 21 races he spent a total of only 33 min., 34 sec. running. Analysis indicated that a jockey's weight is a stimulus to the horse. A 100-lb. jockey is more stirring than a 90-lb. one. Very fast horses do their best running with 110 lbs. on their backs.
That environment has great influence on heredity the water flea daphnia proves. In warm surroundings the female produced eggs without the aid of a male, and all her progeny are females, who too need no male for reproduction. However, when the females are crowded together, as in a glass bottle, or are reared at a coolish temperature, they produce males.
The molecule of both plant and animal life is the chromosome. Chromosomes exist in both the male and female units (gametes) of reproduction. When the male factor prizes itself into the egg, the two sets of chromosomes pair up and then as the cells of the egg divide and multiply the chromosomes do likewise. Every body cell contains the same number of chromosomes. In humans the number is 16. The chromosomes, which must be very highly magnified to be seen, are themselves made up of genes. They are the basic carriers of hereditary traits. Their arrangement within the various chromosomes deter mines the future characteristics of the plant or animal — except as environment later modifies those characteristics. Exhibits of jimson weeds at Cold Spring Harbor last week illustrated this reasoning.
Eugenists. In the U. S. South's slave period, planters followed the economic (if not social) policy of maintaining husky stud and brood negroes for the propagating of brawny slaves. Very closely akin to that policy was the suggestion which President Clarence Campbell of the Eugenics Research Association made in Manhattan. Said he: "Eventually the state must come to recognize the social and economic value of endowing offspring from its efficient stock, a policy for which the social body should receive a hundredfold return. If we come, as we must, to recognize human reproduction as a principle of socio-economic replacement, the same as replacement is recognized and provided for in any well-ordered economic process, we must see that it is in the interest of the whole social body that this replace ment should not only be adequate in quantity but of the best possible quality." He regards Who's Who as "the great American stud book.''