THE BASIS OF HEREDITY.

Press, Volume LIX, Issue 17707, 8 March 1923, Page 4

THE BASIS OF HEREDITY.

ADDRESS BY DR. F. W. HILGENDORF. The Canterbury Philosophical Institute opened its sixty-second session last night, when Dr F. W. Hilgendorf delivered his Presidential address to a large gathering of members of the Institute. The subject was 'The Physical Basis of Heredity," and consisted of an explanation of how the minute structures of the vegetable and animal cell carry and distribute the characters of tiie parents to the offspring. The lecturer nrst explained tnat the limit had been reached beyond which the microscope could show nothing more of the cell or the chromosomes, and then how the discoveries of Mendel had proved that a breeding trial was an indicator of chromosome structure, just as a chemical reaction is an indicator of molecular structure. Mendel's discovery, therefore, had proved not only a work of art in itself, but a key to unlock further secrets, so that by means of the kind of breeding trial that' Mendel suggested, more particulars of the structure of the chromosome were being discovered than the microscope had hinted at the existence of. Tfle recent work of Morgan, of Now York, on Drosophila was detailed so far as it illustrates the mechanism by which the particles which bear the hereditary characters _ are transferred from the parent and distributed among the offspring. Sex, sex-linked characters, and some kinds of mutations were shown to be due to recognisable movements among the chromosomes, and iinally, as the high-water mark in genetic research, the actual positions of the characters in the chromosomes'were shown to be determinable by breeding experiments, so that if a new variation turned up, a single breeding trial would enable a complete and accurate prophecy to be made of how the new character would combine in any cross with all the two hundred odd characters of Drosophila that have so far been studied. Thus individuals differing in a hundred characters could bo mated, and the nature of the offspring could be foretold with meticulous accuracy. Drosophila, being a small fly, breeds rapidly and cheaply, but there was no reason why a similar amount of study should not give us a similar amount of information with regard to our domestic plants and animals, and all the work on Drosophila would be a guide to what could be expected in other organisms. The address was illustrated by some oxcellent photomicrographs, and was .listened to with great pleasure and interest.