Introduction. 



the case of Edward Lambert, whose whole body, with the exception 

 of the face, the palms of the hands and the soles of the feet, was 

 covered with a sort of carapace of horny excrescences which 

 rattled against each other. He was the father of six children, all 

 of whom, from the age of six weeks, presented the same singularity. 

 The only one of these who survived transmitted it to all his sons ; 

 and this transmission, going from male to male, was kept up 

 during five generations. 1 Albinism, rickets, lameness, ectrodactylism 

 and polydactylism, harelip in fact, all deviations from the type, 

 whether they be the result of an excess or of an arrest of organic 

 development are transmissible. These facts are of great interest, 

 as showing that the individual type is subject to the law of heredity, 

 no less than the specific type. 



It is a disputed question whether we must conclude that de- 

 viations from the specific type, anomalies of all kinds such as 

 strabismus, myopia, atrophy and hypertrophy of members remain 

 fixed for ever, or that heredity in such cases is only of a restricted 

 and temporary nature. These individual deviations from law are 

 sometimes transmitted, sometimes not. Experience would appear 

 to show that there is a tendency towards a return to the primitive 

 type. Thus, in the Colburn family, which presented one of the 

 most curious instances of sexdigitism the members of this family 

 had each a supernumerary finger and toe the anomaly continued 

 through four generations ; but, says Burdach, 8 the normal was 

 steadily gaining on the abnormal. 



The ratio was 



ist generation, as i to 35 

 2nd . i 14 



3 f d ,, i 3? 



The return, therefore, to the normal type took place rapidly. 

 This brings us to the important and difficult question of the 

 heredity of acquired modifications. All of which we have spoken 

 the transmission of internal and external structure, of longevity, 

 fecundity, and idiosyncrasies is involved in the very nature of the 

 being as virtually constituted by the act of generation, and belongs 



1 Philosophical Transactions, vol. xvii. and vol. xlix. 



2 Physiologie, vol. ii. p. 251. 



