A study of the degeneracy of the jaws of the human race / by Eugene S. Talbot.
- Talbot, Eugene S. (Eugene Solomon), 1847-1924.
- Date:
- 1892
Licence: Public Domain Mark
Credit: A study of the degeneracy of the jaws of the human race / by Eugene S. Talbot. Source: Wellcome Collection.
Provider: This material has been provided by the University of Toronto, Harry A Abbott Dentistry Library, through the Medical Heritage Library. The original may be consulted at the Harry A Abbott Dentistry Library, University of Toronto.
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![cess of development the physiological units derived from each parent preserved the same ratio to each other in all parts of the growing organisms, each organ would show as much as any other the influence of either parent. But we know that no such uniform distribution is possible. It has been shown that in any mixed aggregate of units segregation must go on. Incident forces will tend ever to cause sepa- ration of the two orders of units from each other, will integrate groups of the one order in one place, and groups of the other order in another place. Hence there must arise not a homogeneous mean between the two parents, but a mixture of organs, some of which mainly follow one parent, and some the other, and this is the kind of mixture ob- servation shows.* This is shown in cases where a child inherits the small jaw of the mother and the large teeth of the father, or vice versa. We seem to inherit, bit by bit, this element from one progenitor, that from another.f When a new character arises, it tends to be inherited at least in a temporary and sometimes in a most persistent manner. We may, on the whole, conclude that inheritance is the rule, non-inheritance the anomaly. In some instances a character is not inherited, from the conditions of life being directly opposed to its development. All races presenting any remarkable peculiarity, such as solid- hoofed swine, Mauchamp sheep, Niata cattle, etc., are instances of the long-continued inheritance of rare derivations of structure. With gout, fifty per cent, of the cases in hospital practice are inherited, and a greater percentage in private families.]; The unanimity of the belief by veterinarians of all nations in the transmission of various morbid tendencies is surprising.^ All scientists have acknowledged the law of inheritance, so that it is unnecessary here to quote from writers who have touched upon this subject, nor does it seem necessary to bring forward illustrations ; but we would like to say here that it does not seem too much to assert that neuroses which are distinctlv hereditable are in a lari^e measure due to abnormalities in the conformation of the cranium and jaws as well. With regard to the inheritance of mutilated structures no definite conclusion has been reached. Godron denies that mutilations have been inherited. He says that different races of men have knocked out their upper incisors, cut off joints of fingers, made holes of immense size through lobes of ears or nostrils, tattooed themselves, made deep gashes in various parts of their bodies, and there is no reason to suppose that these mutilations have been inherited. || How- ever, sometimes a child is born to Sioux Indians bearing these marks.If Pitting of smallpox is never inherited, but the author knows of three instances where scars have been inherited. Exostoses on legs of horses, caused by too much walking on hard roads, are inherited.** A soldier, fifteen years before marriage, lost his eye from purulent ophthalmia, and his two sons were microphthalmic on the same side.ft A cow lost a horn from an accident, with consequent suppuration, and she produced three calves which were hornless on * Herbert Spencer, Principles of Biology. || Ibid. t Francis Galton, Natural Inheritance. *f Dr. Wetherell. X Dr. Garrod. -^^ Dr. Lucas \ Darwin. tt Mr. Sedgwick.](https://iiif.wellcomecollection.org/image/b21202643_0051.jp2/full/800%2C/0/default.jpg)
