Chap. XII. 



INHERITANCE. 



15 



He has had fourteen children, of whom three have inherited additional 

 digits; and one of them, when about six weeks old, was operated on by 

 an eminent surgeon. The additional finger, which was attached by bone 

 to the outer side of the hand, was removed at the joint; the wound 

 healed, but immediately the digit began growing; and in about three 

 months time the stump was removed for the second time by the root 

 But it has since grown again, and is now fully a third of an inch in 

 length, including a bone ; so that it will for the third time have to be 

 operated on. 



Now the normal digits in adult man and other mammals, in birds, and, 

 as I believe, m true reptiles, have no power of regrowth. The nearest 

 approach to this power is exhibited by the occasional reappearance in man 

 ot imperfect nails on the stumps of his fingers after amputation. 33 But 

 man m his embryonic condition has a considerable power of reproduc- 

 tion, for Sir J. Simpson u has several times observed arms which had been 

 cut off in the womb by bands of false membrane, and which had grown 

 again to a certain extent. In one instance, the extremity was " divided 

 into three minute nodules, on two of which small points of nails could be 

 detected ; so that these nodules clearly represented fingers in process of 

 regrowth. TV hen, however, we descend to the lower vertebrate classes 

 which are generally looked at as representing the higher classes in their 

 embryonic condition, we find ample powers of regrowth. Spallanzani 3 * 

 cut off the legs and tail of a salamander six times, and Bonnet eight 

 times, successively, and they were reproduced. An additional digit beyond 

 the proper number was occasionally formed after Bonnet had cut off or had 

 divided longitudinally the hand or foot, and in one instance three additional 

 digits were thus formed. 3 * These latter cases appear at first sight quite 

 distinct from the congenital production of additional digits in the hiker 

 animals; but theoretically, as we shall see in a future chapter they nro 

 bably present no real difference. The larva, or tadpoles of the tailless 

 Batrachians, but not the adults, 3 ' are capable of reproducing lost 

 members. 38 Lastly, as I have been informed by Mr. J. J. Briggs and Mr 

 F. Buckland, when portions of the pectoral and tail fins of various fresh- 



. ™ filer's 'Phys.,' Eng. translai, vol. 

 i., 1838, p. 407. A thrush, however, was 

 exhibited before the British Association 

 at Hull, in 1853, which had lost its 

 tarsus, and this member, it was asserted, 

 had been thrice reproduced : I presume 

 it was lost each time by disease 



34 < Monthly Journal of Medical 

 Science, Edinburgh, 1848, new series, 

 vol. h. p. 890. 



35 'An Essay on Animal Reproduc- 

 tion, trans, by Dr. Matey, 1769, p. 79 



36 Bonnet, < CEuvres d'Hist.' Nat"' 

 torn, v., part i., 4to. edit., 1781, pp 343 

 350, 353. " ' ' 



37 So with insects, the larva? re- 

 produce lost limbs, but, except in one 

 order, the mature insect has no such 

 power. But the Myriapoda, which ap- 

 parently represent the larva? of true in- 

 sects, have, as Newport has shown, this 

 power until their last moult. See an 

 excellent discussion on this whole 

 subject by Dr. Carpenter in his ' Princ. 

 Comp. Phys./ 1854, p. 479. 



38 Dr. Giinther, in Owen's ' Anatomy 

 of Vertebrates,' vol. i., 1866, p. 567. 

 Spallanzani has made similar observa- 

 tions. 



