MAKING MOTHERS BY CHEMISTRY

Evening Post, Volume CXIX, Issue 152, 29 June 1935, Page 25

MAKING MOTHERS BY CHEMISTRY

How some of the basic instincts and psychological behaviour of an animal may be changed from a natural desire to kill to an attitude of tender solicitude by the injection of organic chemicals was demonstrated at Philadelphia in motion pictures before the meeting of the American Philosophical Society, says the "New York Times.1' The demonstration, presented by Dr. Oscar Riddle, of the Carnegie Institution of Washington,' showed a fullgrown unmated female rat tenderly nursing and mothering two helpless pigeon squabs which had been placed in its cage after a few injections of hormones from the pituitary gland had been given to the rat, which, under normal conditions, when hungry, would have devoured the birds. One of the hormones injected was prolactin, the pituitary substance recently demonstrated by Dr. -.Riddle to produce the maternal instinct in animals. Prolactin by itself, however, was found insufficient to produce the personality changes observed in the animal. The ground for the changes had to be prepared by previous injections of another hormone. The finding that the action of one hormone was" ineffective unless preceded by the action of the other was stated by Dr. Riddle to be significant in that it shed new light qp. the chemical forces that control personality. "The administration of this hormone to an otherwise adequately-developed

rat obviously endows the animal with a quite new normal and necessarily psychological experience," he explained. "The apparently necessary and legitimate inference from the induced behaviour is that the introduction of the hormone temporarily adds to such a rat a new element of consciousness:' By the word "instinct," Dr. Riddle added, was meant "an elaborated response, which can occur without previous learning, conditioning, or habit formation." ■ ■ Describing the experiments, which were carried on in association with Dr. Robert W. Bates and Ernest L. Lahr, Dr. Riddle said:—• "We here find—l believe for the first time in the psychic sphere—a normal development or response which rests ■upon a succession or chain of hormonal actions. '. ' "The maternal behaviour demonstrated here, probably involves more than that which may strictly and properly be called the maternal 'instinct.' "Not only does heredity provide a framework for appropriate reflexes and sensori-motor action,, but persistent interest and intelligence proper seem also to share in the newly-invoked activities. "Though the mechanism by which the hormone affects the neural (brain) state is wholly unexplored in this case, there is provided a superior instance of somatic or extra-neural participation in a normal psychic state."