

14 



INHERITANCE. 



Chap. XII. 



races 



the frog. 



Additional digits have been observed in negroes as well as in other iWVO 

 of man, and in several of the lower animals. Six toes have been described 



' ind feet of the newt (Salamandra cristata), and, as it is said of 

 It deserves notice from what follows, that the six-toed newt 

 though adult, had preserved some of its larval characters ; for part of the 

 hyoidal apparatus, which is properly absorbed during the act of meta • 

 morphosis, was retained. In the dog, six toes on the hinder feet have been 

 transmitted through three generations ; and I have heard of a race of six- 

 toed cats. In several breeds of the fowl the hinder toe is double, and is 

 generally transmitted truly, as is well shown when Dorkings are crossed 

 with common four-toed breeds. 30 "With animals which have properly 

 less than five digits, the number is sometimes increased to five, especially 

 in the front legs, though rarely carried beyond that number; but this 

 is due to the development of a digit already existing in a more or less 

 rudimentary state. Thus the dog has properly four toes behind, but in 

 the larger breeds a fifth toe is commonly, though not perfectly, deve- 

 loped. Horses, which properly have one toe alone fully developed with 

 rudiments of the others, have been described with each foot bearing- 

 two or three small separate hoofs : analogous facts have been noticed with 

 sheep, goats, and pigs. 31 



The most interesting point with respect to supernumerary digits is their 

 occasional regrowth after amputation. Mr. White 32 describes a child, three 

 years old, with a thumb double from the first joint. He removed the lesser 

 thumb, which was furnished with a nail ; but to his astonishment it u 

 again, and reproduced a nail. The child was then taken to an eminent 



-rew 



wn 



socket-joint, but again it grew and reproduced a nail. Dr. Struthers men- 

 tions a case of partial regrowth of an additional thumb, amputated when 

 the child was three months old ; and the late Dr. Falconer communicated 

 to me an analogous case which had fallen under his own observation. 

 A gentleman, who first called my attention to this subject, has given 

 me the following facts which occurred in his own family. He himself, 

 two brothers, and a sister were born with an extra digit to each extremity. 

 His parents were not affected, and there was no tradition in the family, 

 or in the village in which the family had long resided, of any member 

 having been thus affected. Whilst a child, both additional toes, which 

 were attached by bones, were rudely cut off ; but the stump of one grew 

 again, and a second operation was performed in his thirty-third year. 



On the inheritance of other anomalies in Polynesians of the Chatham Islands. 



30 ' The Poultry Chronicle,' 1854, p. 



559. 



the extremities, see Dr. H. Dobell, in vol. 



xlvi. of ' Medico-Chirurg. Transactions,' 



1863 ; also Mr. Sedgwick, in op. cit., 31 The statements in this paragraph 



April, 1863, p. 460. With respect to are taken from Isidore Geoffrey St. 



additional digits in the negro, see Hilaire, 'Hist, des Anomalies/ torn. i. 



Prichard, ' Physical History of Man- pp. 688-693. 



kind/ Dr. Dieffenbach (' Journ. Eoyal 32 ^ g quo t e d by Carpenter, ' Princ. 



Geograph. Soc./ 1841, p. 208) says of Comp. Physiology/ 1854, p. 480. 



this anomaly is not uncommon with the 



l. 



it 



ti 





