170 BAEWINIANA. 



Another unanswerable question asked by the Bos- 

 ton reviewers is, Why, when structure and instinct or 

 habit vary — as they must have varied, on Darwin's 

 hypothesis — they vary together and harmoniously, in- 

 stead of vaguely ? We cannot tell, because we can- 

 not tell why either varies at all. Tet, as they both 

 do vary in successive generations — as is seen under 

 domestication — and are correlated, we can only ad- 

 duce the fact. Darwin may be precluded from our 

 answer, but we may say that they vary together be- 

 cause designed to do so. * A reviewer says that the 

 chance of their varying together is inconceivably 

 small ; yet, if they do not, the variant individuals must 

 all perish. Then it is well that it is not left to chance. 

 To refer to a parallel case : before vre were born, 

 nourishment and the equivalent to respiration took 

 place in a certain way. But the moment we were 

 ushered into this breathing world, our actions promptly 

 conformed, both as to respiration and nom'ishment, 

 to the before unused structure and to the new sur- 

 roundings. 



" Now," says the Examiner^ " suppose, for instance, 

 the gills of an aquatic animal converted into lungs, 

 while instinct still compelled a continuance under 

 water, would not drowning ensue ? " No doubt. But 

 — simply contemplating the facts, instead of theoriz- 

 ing — we notice that young frogs do not keep their 

 heads under water after ceasing to be tadpoles. The 

 instinct promptly changes with the structure, with- 

 out supernatui'al interposition — ^just as Darwin would 

 have it, if the development of a variety or incipient 



