102 ENGLISH MEN OF SCIENCE. [CHAP. 



affected ; mother delicate and phthisical." I 

 can find only two cases, neither very strongly 

 marked, in which both parents are described 

 as unhealthy, although marriages between such 

 persons are not infrequent. The returns seem 

 to show that the issue of these marriages are 

 barely capable of pushing their way to the front 

 ranks of life. All statistical data concur in prov- 

 ing that healthy persons are far more likely 

 than others to have healthy progeny ; and 

 this truth cannot be too often illustrated, until 

 it has taken such hold of the popular mind, 

 that considerations of health and energy shall 

 be of recognized importance in questions of 

 marriage, as much so as the probabilities of 

 rank and fortune. 



I may mention, as a fact that corroborates 

 my belief in the exceptionally good physique of 

 scientific men, that I find the average height 

 of those who have sent me returns, to be half 

 an inch above that of their fathers. 



