MYSTERIES OF LIFE.

Hauraki Plains Gazette, Volume XXXVII, Issue 5046, 1 November 1926, Page 4

MYSTERIES OF LIFE.

HEREMTT AND ENVUKONMENT.

PROOF OF LAM ARC R r AN THSORY-

In all our intensive study of the mysteries of life the parts, played by heredity and environment as factory, modifying evolution have long been in ■dispute ('states a correspondent to a London paper). Sometimes the heredity factor gets more support and at others environment.

The British Association meeting of 1926 will be memorable for having given publicity to a series- of experiments with rats which have been going on for six years and which k,eem to ha,ve given support to. the importance of heredity and breeding. It was in the psychological section that Professor W. McDougall, of Harvard University, described an experiment in breeding rats, which, he claimed, confirmed the Lamarckian hypothesis.

This hypothesis, he observed, was the proposition that species might Ichange, might undergo evolution, through the efforts of the individual parents to adapt themselves to the conditions of life. The hypothesis had for some time been regarded with disfavour by scientists, who did not understand how the germ plasm could be affected by the individual, and acquired characteristics be thus transmitted ; but, not having himself regarded the. evidence against it as; conclusive, he determined some years ago to embark on a,n experiment designed to give positively affirmative or 'negative results. This, experiment was begun six years ago, apd whito ra.ts were chosen for it.

The Original white rat stock was; divided into two parts for the purpose, ©f two different tests, one being designed to perform a task of finding a •way out of simple water mains, and ihe other to learn to avoid a p rticu<lar channel on coming into contact ■with a certain signal—in other words, an avoidance of re-action. The experiments had now extended through .17 generations' of rats, three generations being dealt with each year. The •second experiment had given quite positive results, which he could not

•explain by any other theory than the Lamarckian hypothesis. Though thq results, were not conclusive, they showed that on the whole 'rats from stock trained in this particular way learned to escape more rapidly than those from untrained stock similar in all other respects. Professor McDougall proposes to go on with his experiments another 20 years; this 1 is only an interim report.