HEREDITY OF DISEASES. 31 



days ; most of them have been the subjects of repeat- 

 ed attacks of weed ; all are affected, particularly in 

 the spring, with scurfiness of the skin of the hind ex- 

 tremities, and excessive itchiness, and lose at a very 

 early age their flatness and smoothness of limb." 



" The faults occur, to a greater or less degree, in 

 all the stock of this horse by many different mares, 

 and are distinctly traceable to the third generation." l 



The following case of bilateral symmetry in the 

 heredity of bony tumors, reported by Dr. Paget, is of 

 particular interest, as it illustrates a peculiarity which 

 is also observed in other diseases : " A boy, six years 

 old, was in St. Bartholomew's Hospital, five years ago, 

 who had symmetrical tumors on the lower ends of his 

 radii, on his humeri, his scapulae, his fifth and sixth 

 ribs, his fibulse, and internal malleoli. On each of 

 these bones, on each side, he had one tumor, and the 

 only deviations from symmetry were that he had an 

 unmatched tumor on the ulnar side of the first pha- 

 lanx of his right forefinger, and that each of the 

 tumors on the right side was rather larger than its 

 fellow on the left. I saw this child's father, a healthy 

 laboring-man, forty years old, who had as many, or 

 even more, tumors of the same kind as his son ; but 

 only a few of them were in the same positions. All 

 these tumors had existed from his earliest childhood ; 

 they were symmetrically placed, and ceased to grow 

 when he attained his full stature ; since that time they 

 had undergone no apparent change. None of this 

 man's direct ancestors, nor any other of his children, 

 had similar growths ; but four cousins, one female 



1 Journal of the Royal Agricultural Society, vol. xiv., p. 122. 



