. Biology and man. Biology; Human beings. After Morgan MUTATIONS OF THE FRUIT-FLY In the course of systematic observation and experimenting, Morgan and his associates found hundreds of individual fruitflies that arose as distinct types year after year. They differed from their parents in a single character, sometimes in several characters — eye color, wing shape, body color or shape, and many other details showed at least that without modifying the parent, something may happen to the germ cells in a way that alters the characteristics of the offspring. It did not enable us to produce particula
. Biology and man. Biology; Human beings. After Morgan MUTATIONS OF THE FRUIT-FLY In the course of systematic observation and experimenting, Morgan and his associates found hundreds of individual fruitflies that arose as distinct types year after year. They differed from their parents in a single character, sometimes in several characters — eye color, wing shape, body color or shape, and many other details showed at least that without modifying the parent, something may happen to the germ cells in a way that alters the characteristics of the offspring. It did not enable us to produce particular mutations at will, nor did it tell us exactly how the X rays exert their influence. Among these mutants, as among those which appeared "naturally" in the laboratories of other investigators, were some with white eyes, some with smaller wings, and many other freaks. Many of these were entirely new in the sense that they had not been found by other experimenters or observed to occur "naturally". In recent years startling results have been produced by treating plants with the drug colchicine, obtained from a plant of the crocus family. The first effect observed is a great increase in the size of parts treated, often associated with coarse tissues or rank growth. The giant character is inherited. Closer study indicates that the colchicine acts upon cells at the time the nucleus divides, by keeping newly formed chromosomes from separating into two sets. The result is a doubling of the chromosomes, and a modifying of the growth and other characteristics. A "harvest spray" containing colchicine has been used to keep apples of Mcintosh and other varieties from dropping off the stem too soon while ripening. This spray improves the quality as well as the yield, from the orchardist's point of view. We have every reason to think that new forms are constantly arising, more 513. Please note that these images are extracted from scanned page images that may ha
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