296 STUDIES IN THE EVOLUTION OF ANIMALS 



Six digits have also been observed in negroes as well as in 

 other races. Also in hind-foot of a Newt, and in hind-feet of 

 several generations of Cats. 1 In several breeds of Fowl the hinder 

 toe is double, and is transmitted truly. 



Dr. J. W. Ogle gives a case of inheritance of deficient phalanges 

 during four generations. 2 



Mr. Darwin gives references for all he states. 



What we have particularly to remember is that monstrosities, 

 although diluted with normal blood, (a) may increase in number in 

 subsequent generations, and (U) may spread from the hands to 

 the feet also. 



From this we may infer that the disturbing influence in the 

 hand nerve-centre, which causes the monstrosity in that limb, is 

 liable to diffuse itself along the spinal cord and influence the 

 nerve-centre of the foot also. 



A few detailed cases will impress on the reader's mind not only 

 this sex-digitate feature in Man, but also the persistence with which 

 it may be inherited, although diluted by normal blood. 



Godehen in 1751 recorded the oft-quoted history of one Grezio 

 Calleja, a poly dactyl. 3 He had six fingers and six toes in each 

 limb. He had four children, three boys and one girl. The eldest 

 boy, Salvator, had six digits in each limb, but the supernumerary 

 digit in the hands was not so well formed as those of the father. 

 On the contrary those of the feet were better formed. The other 

 three children had the normal number, five, in both hands and feet ; 

 but all excepting the youngest had deformities of fingers more or 

 less marked. So only one of the four children of Grezio had 

 normal limbs. The children of this latter were normal. On the 



1 Brit, and For. Meet. Chirurg. Rev., April 1872. 



2 J. T. Cunningham, translator of Elmer's Organic Evolution, says he has a Cat with 

 six toes on every foot. 



3 Hist, des Anomalies, by Isidore Geoffrey St. Hilaire, vol. i. p. 699, 



