Elementary biology; an introduction to Elementary biology; an introduction to the science of life elementarybiolog00grue Year: 1924 460 ELEMENTARY BIOLOGY to these cells some of the germ plasm from which it had itseli developed. In other words, the eggs produce the organism, not the organism the eggs (see Fig. 246). According to this notion it would be impossible for the ex- perience of an individual to influence the germ cells in such a way as to make the offspring show the effects. For example, the result of exercise or of mutilations or of sickness should not appear in the following genera
Elementary biology; an introduction to Elementary biology; an introduction to the science of life elementarybiolog00grue Year: 1924 460 ELEMENTARY BIOLOGY to these cells some of the germ plasm from which it had itseli developed. In other words, the eggs produce the organism, not the organism the eggs (see Fig. 246). According to this notion it would be impossible for the ex- perience of an individual to influence the germ cells in such a way as to make the offspring show the effects. For example, the result of exercise or of mutilations or of sickness should not appear in the following generation. As a matter of fact we have no evidence whatever that modifications produced in 61 62 63 Fig. 246. The idea of the germ plasm When a fertilized egg, g, develops into a new individual, d, part of the protoplasm becomes the body, or soma, and part remains germ, within the body, where it is nurtured The germ is not a product of the body in any sense. Each body, b^, bo, /'g, is a branch, or development, of the germ, but the stream of germ material is continuous. The nature of the germ determines the kind of individuals or persons that will develop; the body does not influence the germ an individual in the course of his lifetime are ever reproduced in the offspring, although you will find many people who firmly believe that such modifications are actually transmitted. 482. Sports. The appearance from time to time of an un- usual kind of individual that the breeders and horticulturists call a sport would suggest that germ plasm may undergo important changes. There appeared on a farm in Massachu- setts, in 1791, a queer sheep with a long body and very short, crooked legs. This ' ancon ' ram was kept for many years, and had many offspring with normal sheep. All the hybrids showed the same curious character. This 'turnspit' type of
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