230 CROSSING AND CLOSE-INTERBREEDING. 



This proportion, too, would not be a direct one; for, 

 if the diseases involved many parts, their symmetrical 

 effect would measurably poise the balance which, action 

 in one part alone, would have more disturbed. 



A man, however, very disproportionately developed, 

 may be free from all specific diseases ; yet, if he breed 

 with even the most distant of traceable relatives, he 

 probably will, either, be sterile, or give birth to off- 

 spring which will be sterile; and he, and his offspring, 

 will be of much weakened constitution. The well- 

 bred (?) pig, with the regulation reduction of legs, of 

 snout, of front of the head, of tusks, and with bristles 

 suppressed, may be free from all particular diseases, 

 yet it will most probably be sterile with even distant 

 relatives, and even with others of the same breed; 

 whereas, the pig that roams the woods for a living, and 

 has the characters, above mentioned, proportionately 

 developed, instead of having them reduced; may have 

 every disease, peculiar or common to pigs, yet it will 

 be very prolific, in any degree of close-interbreeding. 



Darwin cannot understand why this is so. He can 

 appreciate, how there is evil from the mere augmenta- 

 tion of morbid tendencies ; or, how there is evil in par- 

 ticular parts from the aggravation of the parents' defects 

 in those parts ; but, he is at a complete loss, to under- 

 stand how, or why, the effects upon the aggregate, and 

 upon the reproductive system, are wrought. His idea, 

 that he may vary an animal or plant, ad lib., and mould 

 it, to any form he pleases, precludes his arriving at the 

 truth, namely, that normal coordination consists solely 

 with the development of all the parts of the given 



