144 



HEREDITY. 



Pathological 

 Atavism. 



The Fact of 

 Atavism. 



Pepper's 

 Observations. 



mainly from a pathological point of view, and it 

 signifies the reappearing of morbid conditions of 

 distant ancestors not manifest in the immediate 

 parents. Sir T. Watson in his lectures on "The 

 Practice of Medicine," gives the following case 

 as an illustration of pathological atavism: "A 

 deaf mute man married a woman whose hearing 

 was perfect and had two children by her ; one was 

 a deaf mute son, who died childless, the other a 

 hearing daughter, who married a hearing man 

 and gave birth to two deaf mute daughters and a 

 hearing son. The son married a woman who was 

 also of good hearing, and had by her a deaf mute 

 son; one of the daughters married a deaf mute 

 and bore a hearing son." 



The fact of atavism is now generally admitted 

 by the medical profession and all up to date stu- 

 dents of heredity. The frequent appearance of 

 physical and mental characteristics possessed by 

 distant ancestors has forced all unbiased inves- 

 tigators to admit that in some mysterious way 

 qualities that have been absent for one, or even 

 several, generations do occasionally reappear. Ac- 

 cording to Pepper, "Gout, consumption, insanity, 

 and other diseases frequently disappear for one, 

 two or more generations in a family, and then re- 

 turn in a manner evidently due to heredity, 

 through interrupted or latent transmission." 

 Anatomists occasionally find muscles and parts 

 of organs that have been long extinct, though they 

 were formerly possessed by the species. 



The law of atavism is not limited, as some have 

 supposed, to physical and pathological conditions, 

 but is applicable to all mental and moral attributes 



