Chap. XII. INHERITANCE. 459 



four-toed breeds.** "With animals which have properly less than 

 five digits, the number is sometimes increased to five, especially on 

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

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

 less rudimentary state. Thus, the dog has properly four toes liehindj 

 but in the larger breeds a fifth toe is commonly, though not per- 

 fectly, developed. 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 cows, slieei^, goats, and pigs.^ 



There is a famous case described by Mr. White of a child, three 

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

 the lesser thumb, wliich was furnished with a nail; but to his 

 astonishment it grew again and reproduced a nail. The child was 

 then taken to an eminent Loudon surgeon, and the newly-gi'own 

 thumb was removed by its socket-joint, but again it gi-ew and re- 

 produced a nail. Dr. Struthers mentions a case of the partial 

 re-growth of an additional thiunb, amputated when a child was 

 three months old; and the late Dr. Falconer ccmmunicated to me 

 an analogous instance. In the last edition of this work I also gave 

 a case of the regrowth of a supernumerary little-finger after ampu- 

 tation ; but having been informed by Dr. Bachmaier that several 

 eminent surgeons expressed, at a meeting of the Anthropological 

 Society of Munich, great doubt about my statements, I have made 

 more particiilar inquiries. The full information thus gained, to- 

 gether with a tracing of the hand in its present state, has been laid 

 before Sir J. Paget, and he has come to the conclusion that the de- 

 gree of regrowth in this case is not greater than sometimes occurs 

 with normal bones, esjoecially with the humerus, when amputated 

 at an early age. He further does not feel fully satisfied atout the 

 facts recorded by Mr. Wliite. This being so, it is necessary for me 

 to withdi'aw the view which 1 formerly advanced, with much hesi- 

 tation, chiefly on the ground of the supposed regrowth of additional 

 digits, namely, that their occasional development in man is a case 

 of reversion to a lowly-organised progenitor provided with more 

 than five digits. 



I may here allude to a class of facts closely allied to, but 

 somewhat different from, ordinary cases of inheritance. Sir 

 H. Holland^* states that brothers and sisters of the same 



^2 'The Poultry Chronicle,' 1854, well-developed toes on each hind limb, 



p. 559. besides the ordinary rudiments ; and 



^^ The statements in this paragraph her calf by an ordinary bull had extra 



are taken from Isidore Geott'roy St. digits. This calf also bore two calves 



Hilaire, ' Hist, des Anomalies,' torn. i. having extra digits. 



pp. 688-693. Mr. Goodman gives, ^* ' Medical Notes and Reflections,' 



'Phil. Soc. of Cambridge,' Nov. 25, 1839, pp. 24, .34. See, also. Dr. P 



1872, the case of a cow witn three Lucas, ' L'Hered. Nat.,' tom. ii. p. 33, 



