LATVS OF HEREDITY. 19 



marked Ms descendants for several generations, and amounts to almost 

 a family characteristic. 



Racliitis, tuberculosis, albinism, ectrodactyliErm and polydactylism, labia 

 leporena, as well as many other deviations from the natural type, may become 

 developed, established, and then hereditarily transmitted. These facts are not 

 only of interest as applied to the human family, but they are of great import- 

 ance to those who are engaged in the breeding and improvement of all kinds 

 of animals, as from these we determine that all deviations from the original 

 type, whether the result of excess or arrest of organic development, are hered- 

 itary and transmissible, and also that the individual type is but little, if any, 

 less subject to the laws of heredity than the specific or original type. It must 

 be remembered, in this connection, that neither the specific nor individual 

 deviations are always transmitted, as it is well known that sometimes they do 

 not appear to be. Hence, it is questionable whether we must conclude that 

 deviations from the specific type are fixed permanently, or the heredity 

 restricted. Observation leads us to believe that there exists a tendency to 

 return to the original or specific type. This is shown by the case of Colburn, 

 reported by Burdach. Each of this family had a supernumerary toe and 

 finger, the anomaly continuing through four generations. In this case the 

 normal steadily gained upon the abnormal ; as, in the first generation, there 

 was but one with the proper number of toes and fingers to 35 with six ; in the 

 second generation, there was one to 14, and in the third, one to 3 — this shows 

 a rapid return toward the normal type. 



Having briefly referred to the transmission of anomalies of structure, lon- 

 gevit}", fecundity and idiosyncrasies, etc., as more particularly relating to, or 

 involved in, the very nature of the animal or being as constituted through the 

 process of generation, I now propose to devote a few words to what I conceive 

 to be a more difiicult, as well as more important, phase of the subject under 

 consideration — that of the relation of heredity to more strictly acquired modi- 

 fications; such, for example, as vital or nervous force, mental habits and 

 muscular strength and power, as developed in the nervous and muscular 

 system, through both education and exercise. I do not think there can be a 

 doubt as to the transmission of muscular strength, as well as the difi:erent 

 forms of motor energy. As a type, the Celt excels as a pugilist — there being 

 families of prize-fighters. Formerly, there have been families of athletes, 

 etc., etc. 



Galton, who has given this subject considerable attention, declares, "that 

 the best oarsmen, wrestlers, athletes, dancers, etc., generally belong to a small 

 number of families, among whom strength and skill are hereditary'." 



Horse breeders are familiar with the fact, that certain types of the horse 

 possess a superiority of motor energy and muscular strength over others, and 

 try to make their selection in breeding accordingly. It must be admitted, 

 however, that their study of this subject has, heretofore, been top much of an 

 empirical order — their knowledge being derived almost wholly from observa- 

 tion, and not from a proper study of the fixed laws regulating hereditaiy 

 trausmissioo. 



