UNDER THE APPLE-TREES 



hold upon life, — an abounding, or plus, vitality, — 

 while the opposite is true of others. In a brood of 

 chickens or a litter of pigs or of puppies this in- 

 equality of the gift of vitality is often very pro- 

 noimced; it of course has its prenatal causes, 

 but they are involved in the hidden activities of 

 the cells. The term "a good constitution" has a 

 scientific value, though quite beyond the tests of 

 scientific analysis. The term "constitution" is only 

 a name for a certain totality of physical endowment, 

 as the word "vitality" is only a name for certain 

 activities in matter; but if the latter has no stand- 

 ing in the court of science or of philosophy, neither 

 could the former have standing. Yet how very 

 real both are to us. The diathesis of a person — his 

 predisposition to certain diseases — is a very real 

 factor in his physical life. No doubt by artificial 

 or arbitrary selection a race of very long-lived men 

 might be developed. By allowing only the off- 

 spring of long-lived parents to marry, the term of 

 human life could doubtless be greatly lengthened. 

 But Nature does not work on this plan. She con- 

 stantly crosses these opposite tendencies, because 

 her solicitude is not about the few, the exceptional, 

 but about the many, or the average. Tall men are 

 prone to marry short women, one temperament 

 to unite with its complementary, the robust with 

 the delicate. Robert Browning marries the invalid 

 Elizabeth Barrett. In the human species Nature 

 284 



