AMERICAN INSTITUTE. 499 



continue to exist as a race only as long as we are " propped up 

 by infusion of European blood." Now this is all very interesting 

 to us, for no people in the world desire more than we to know 

 what older nations think of us, — not dreaming in our simplicity 

 that we know more of ourselves than they do. 



But, unfortunately for all these theories, w^e have the evidences 

 which have been recounted in this paper to prove that climate has 

 nothing directly to do with it; that wlien men and animals in- 

 habit a new country, they are liable for a time to be put to shifts, 

 as the American race were, until they reached the " Genesee 

 country " in their westward progress, living more on rye and 

 maize than is consistent with man's highest physical development. 

 As the race proceed westward these causes are being removed, so 

 that at the present time the American may subsist on the best of 

 food as easily as any man on earth. The continual influx of flour 

 into the eastern states from the great natural wheat growing 

 region of the west, is removing all cause that ever existed for this 

 imputation against any class in this country. 



But the conclusion must not be drawn from what has been said, 

 that no advantage is to be derived from the introduction of foreign 

 varieties of stock. As the condition of animals improves as 

 warm and comfortable stables are substituted for the stack yard 

 and hovel of former times, we should by judicious crossing, take 

 immediate advantage of these improvements. The food of do- 

 mestic animals is now hardly cheap enough any where in this 

 country to allow us to leave them exposed with profit. If that 

 course be once decided on, however, by all means shun fine foreign 

 breeds. But true profit is found now almost universally in fine 

 stock, high feeding, and good care. 



UNDER WHAT CIRCUMSTANCES VARIATIONS BECOME 



PERMANENT, 



As we have seen that variations in animals and plants arise 

 out of necessities, and are adaptations to certain ends, so they are 

 permanent only while the pressure of the circumstances that pro- 

 duced them continues to act. Thus, in rich, succulent pastures, 

 the cow, after a few generations, assumes that shape that produces 

 most milk, and the tendency to the production of milk becomes 



