

12 



INHERITANCE. 



Chap. XII. 



finitely diversified characters, by which the domestic races of 

 animals and plants are distinguished, nothing need be said ; for 

 the very existence of persistent races proclaims the power of 



inheritance. 



A few special cases, however, deserve some consideration. It 

 might have been anticipated, that deviations from the law of 

 symmetry would not have been inherited. But Anderson 23 states 

 that a rabbit produced in a litter a young animal having only 

 one ear; and from this animal a breed was formed which 

 steadily produced one-eared rabbits. He also mentions a bitch, 

 with a single leg deficient, and she produced several puppies 

 with the same deficiency. From Hofacker's account 24 it appears 

 that a one-horned stac: was seen in 1781 in a forest in G-ermanv, 

 in 1788 two, and afterwards, from year to year, many were 



observed with only one horn on the right side of the head. 

 A cow lost a horn by suppuration, 25 and she produced three 

 calves which had on the same side of the head, instead of a 

 horn, a small bony lump attached merely to the skin ; but 

 we here approach the doubtful subject of inherited mutilations. 

 A man who is left-handed, and a shell in which the spire turns 

 in the wrong direction, are departures from the normal though 

 a symmetrical condition, and they are well known to be inherited. 



Polydactylism. — Supernumerary fingers and toes are eminently liable, as 

 various authors have insisted, to transmission, but they are noticed here 

 chiefly on account of their occasional regrowth after amputation. Poly- 



dactylism graduates 26 by multifarious steps from a mere cutaneous ap- 

 pendage, not including any bone, to a double hand. But an additional 

 digit, supported on a metacarpal bone, and furnished with all the proper 

 muscles, nerves, and vessels, is sometimes so perfect, that it escapes detec- 

 tion, unless the fingers are actually counted. Occasionally there are 

 several supernumerary digits; but usually only one, making the total 

 number six. This one may represent either a thumb or finger, being 

 attached to the inner or outer margin of the hand. Generally, through 

 the law of correlation, both hands and feet are similarly affected. I have 

 tabulated the cases recorded in various works or privately communicated 



23 ' Eecreations in Agriculture and 

 Nat. Hist.,' vol. i. p. 68. 



24 'Ueber die Eigenschaften/ &c, 

 1828, s. 107. 



25 Bronn's < Geschichte der Natur/ 

 Band ii. s. 132. 



26 Vrolik has discussed this point at 

 full length in a work published in Dutch, 

 from which Mr. Paget has kindly trans- 

 lated for me passages. See, also, Isidore 

 Geoffroy St. Hilaire's • Hist, des Ano- 

 malies/ 1832, torn. i. p. 684. 



