Heredity / by J. Arthur Thomson.

  • Thomson, J. Arthur (John Arthur), 1861-1933.
Date:
1908
Catalogue details

Licence: In copyright

Credit: Heredity / by J. Arthur Thomson. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

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    chrysanthemums, by experimental cleverness and infinite patience, may be surpassed in the future if breeders and cultiva- tors can attain to a better understanding of the more or less obscure laws of inheritance on which all their results depend. Importance in Biological Theory.—The study of heredity is also of fundamental importance in the domain of pure science, in the biologist's attempt to interpret the process of evolution by which the complexities of our present-day fauna and flora have gradually arisen from simpler antecedents. For heredity is obviously one of the conditions of evolution,—of continuance as well as of progress. There would have been heredity even if there had been a monotonous world of Protists without any evolution at all, but there could not have been any evolution in the animate world without heredity as one of its conditions. The study of heredity is inextricably bound up with the problems of development, reproduction, fertilisation, variation, and so on ; in short, it is one of the central themes of Biology. § 2. What the Terms Mean The Terms are tinged with Metaphor.—In the popular, if not also in the biological mind, there often lurks the idea of a hypothetical agent possessing the organism and uniting the congeries of its characters. Expressed in diverse ways, there is a prevalent conception of an organismal unity which gives coherence to the sum of quahties (see Sandeman, 1896). Espe- cially in reference to higher animals with a rich mental hfe, many find it impossible not to think of a soul or self to which the body belongs. Naturally enough, therefore, the reappear- ance in the offspring of qualities which characterised its parents or its ancestors has been persistently likened to the inheritance of a legacy. But this is to some extent a metaphorical expres- sion, and not without its dangers. At first the Organism and the Inheritance are Identical—A
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