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Show 22 INIIERITANCE. CHAP. XII. . . d not answer to pair two jonquils, as the coloured bn·d It oest t strong or is even brown. So again, co l ou r then· comes o.u oo . d ' the young birds rarel y m. h er1. t if ~wo crested. ~~n;~:.ci~ ~;e;t:I~ebirds a narrow space of bare skin ~his ~harachtcr b. 1 f the head where the f athcrs arc up-turned IS left on t c ac c 0 d h bo' th parents are thus c h aract ari·s e d' to form the crest, an ' w en . e and the crest itself fails to be the bareness becomes cxcessiv ' ' . . ) dcvclo eel. Mr. Hewitt, speaking of Laced Selmght Bantams, 58 ~hat " why this should be so, I know not, but I am c?n~ Je~lt that' those that are best laced ~rcqucnt~y produce o~spl:mg f f ·f ct I.Il their markmgs, whilst those exhibited very ar rom pm e b d lf . 1 . l have so often proved suecessful, were re by royse , w nc 1 < h . f heavily-laced birds with those that were from t e umon o ,c scarcely sufficiently laced." I . . lar· fact that although- several deaf-mutes often t IS a smgu < ' • b occur in tho same family, and though their cousi?S and ot er relations are often in the same condition, ye~ tbeu parents are l . d f utcs rro o-ive a sinole mstance : l\Ot one very rare y ea -m · b . . sc l 10l ar ou t Of 1L:1'.8 , who were at the same time• m the Londo• n Institution, was the child of parents similarly affhcted. So agm~, when a male or a female deaf-mute marries a sound pe~·son,. therr children are most rarely affected: in Ireland out of 203 children ·thus produced one alone v;as mute. Even when both ,?aren~s have been deaf-mutes, as m the case of forty-one marnages m the United States and of.six in Ireland, only two deaf an~ dumb children were produced. Mr. Sedgwick,59 in comment~ng on this remarkable and fortunate failure in the power of. transmission in the direct line, remarks that it may possibly be owing to "excess having reversed the action of some natural law in development.'' But it is safer in the prese~t st~t~ of our knowledge to look at the whole case as simply umntelbgible. With respect to the inheritance of structures mutilated by injuries or altered by disease it is difficult to come to any 67 Becbstciu, 'Naturgesch. Deutschlanda,' b. iv. s. 462. Mr. Brent, a great breeder of canaries, informs me that be believes tllat these statements are correct. us • The Poultry Book,' by W. B. Tegctmcicr, 1866, p. 245. . r;g 'British and Foreign Mcd.-Chirnrg. Review,' July, 18Gl, pp. 200-204 .. l\1r. Sedgwick bas given such full deta1ls on this subject, with ample r fcrcnccs, that I need refer to no other authorities. CHAP. XII. INHERITANCE. 23 definite conclusion. In some cases mutilations have been practised for a vast number of generations without any inherited result. Godron has remarked ao that different races of man have from time immemorial knocked out their upper incisors, cut off joints of their :fingers, made holes of immense size through the lobes of their ears or through their nostrils, made deep gashes in various parts of their bodies, and there is no reason whatever to suppose that these mutilations have ever been inherited. Adhesions due to inflammation and pits from the small-pox (and formerly many consecutive generations must have been thus pitted) arc not inherited. With respect to Jews, I have been assured by throe medical men of the Jewish faith that circumcision, which has been practised for so many ages, has produced no inherited effect; Blumenbach, on the other hand, asserts rH that in Germany Jews are often born in a condition renderino- cir- b cumcision difficult, so that a . name is there applied to them signifying " born circumcised.'' The oak and other trees must have borne galls from primeval times, yet they do not produce inherited excrescences ; many other such facts could be add need. On the other hand, various cases have been recorded of cats do~s'. and horses, v~hich have had their tails, legs, &c., amputated or mJm·~d,_ producmg offspring with the same parts ill-formed; but as It IS not at all rare for similar malformations to appear spontaneously, all such cases may be due to mere coincidence. N evortheless, Dr. Prosper Lucas has given, on good authorities, such a long list of inherited injuries, that it is difficult not to believe in them. Thus, a, cow that had lost a horn from an accident with consequent suppuration, produced three calves which were .hornless on the same side of the head. vVith the horse, there seems hardly a doubt that bony exostoses on the legs, caused by too much travelling on hard roads, are inherited. Blumenbach records the case of a man who had his little finfl"er on the right hand a~most cut off, and which in conseque;ce grew m:oo~md, and h1s sons had the same finger on the same hand Similarly crooked. A soldier, :fifteen years before his marriage, lost his left eye from purulent ophthalmia, and his :o ' Dc_l'Espcce,' tom. ii., 185!), p. 299. 61 'Phllosopb. Magazine,' vol. iv., 1799, p. 5. |