An introduction to the study of heredity / by E.W. Macbride.

  • MacBride, E. W. (Ernest William), 1866-1940.
Date:
[1924]
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: An introduction to the study of heredity / by E.W. Macbride. Source: Wellcome Collection.

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    as to the causes of the production of the wretched pathological mutants with which he has worked. As Tornier himself has pointed out, if we contrast the vigorous, healthy life of a wild boar with the sluggish, insanitary existence of. a farmyard pig, we see ample reason for the appearance of a germ-weakening in the latter; and if we compare the skulls of the two animals as shown in Fig. 36, we see in the skull of the domestic pig the same fore-and-aft shortening which we noticed in the skull of the gold-fish contrasted with that of the carp. It is true that the mam malian egg contains no yolk, because the embryo derives all its nourishment from the womb, but the head of the embryo is immersed in a sac (the amniotic sac), tensely filled with fluid, and abnormally high amniotic pressure has already been indicated by our leading orthopaedist, Sir Robert Jones, as the cause of many congenital deformities. As to the difference in vigour between the normal and weakened types, anyone who has ever handled wild mice and tame white mice will require no further demonstration of the truth of Tornier’s views in this respect. It was the great mistake of Darwin in that classic book, The Origin of Species, that he