HEREDITARY TRAITS. 217 



Hanover and in England, a similar fecundity has been shown 

 in two generations out of three. Sir W. Herschel was one of 

 a family of twelve children, of whom five were sons. He him- 

 self did not marry till his fiftieth year, and had only one son. 

 But Sir John Herschel was the father of eleven children. 



Of constitutional peculiarities those affecting the nervous 

 system are most frequently transmitted. We do not, however, 

 consider them at this point, because they are viewed ordinarily 

 rather as they relate to mental and moral characteristics than 

 as affections of the body. The bodily affections most com- 

 monly transmitted are those depending on what is called 

 diathesis a general state or disposition of the constitution 

 predisposing to some special disease. Such are scrofula, 

 cancer, tubercular consumption, gout, arthritis, and some 

 diseases specially affecting the skin. It would not be de- 

 sirable to discuss here this particular part of our subject, 

 interesting though it undoubtedly is. But it may be worth 

 while to note that we have, in the variety of forms in which 

 the same constitutional bad quality may present itself, 

 evidence that what is actually transmitted is not a peculiarity 

 affecting a particular organ, even though in several successive 

 generations the disease may show itself in the same part of 

 the body, but an affection of the constitution generally. We 

 have here an answer to the question asked by Montaigne in 

 the essay from which we have already quoted. The essay 

 was written soon after he had for the first time experienced 

 the pangs of renal calculus : ' Tis to be believed/ he says, 

 * that I derived this infirmity from my father, for he died 

 wonderfully tormented ' with it ; he was * never sensible of 

 his disease till the sixty-seventh year of his age, and before 

 that had never felt any grudging or symptom of it ' . . . ' but 

 lived till then in a happy vigorous state of health, little sub- 

 ject to infirmities, and continued seven years after in this 

 disease, and dyed a very painful death. I was born about 

 twenty-five years before his disease seized him, and in the time 

 of his most flourishing and healthful state of body, his third 

 child in order of birth : where could his propension to this 



