400 BOARD OP AGRICULTURE. 



with, attains its full perfection only in a limited zone, and all yield 

 to such modifications as are imposed upon them by a greater or 

 less amount of heat and cold. 



On the sides of mountains the same gradation is noticeable. On 

 their warm and sunny slopes, a luxui'iant vegetation abounds, but 

 as we ascend to a cooler belt of air, and a poorer soil, a new flora 

 presents itself. This again quickly gives place to another of 

 diminished life and vigor, as we continue the upward journey, till 

 we arrive at the bald and barren summit. Thus in the changing 

 form, fibre, texture, fruit, chemical qualities, and general distribu- 

 tion in the vegetable world, do we trace the workings of this all- 

 embracing and irresistible law. So vast, and yet so m.inute are the 

 changes which are being continually wrought by climate influence 

 in the leafy kingdom of life. Like the waters of the ocean, with 

 which winds and tempests sport, this sea of vegetable life ebbs 

 and flows over the face of the globe, in strict obedience to subtle 

 forces of nature, whose power they cannot resist. 



However fruitful the field for observing the operations of the 

 same laws, pi'esented by the animal kingdom, our subject does not 

 demand that we linger long upon it ; for it is not my purpose to 

 discuss how far structural changes in the animal organization are 

 dependent upon inherited variation, (themselves the result of accu- 

 mulated, methodical selection), as contrasted with such changes as 

 are traceable directly to the action of p'hysical conditions. How- 

 ever great and important the former may be, the law of the latter 

 will always prove the stronger. 



The marvellous improvements in our domestic animals, wrought 

 by modern skill, can only be maintained up to a high level by a 

 constant and unremitted application of that intelligent culture 

 which perfected them, and even then, in process of time, the more 

 powerful influence of climate will assert its demands, and, in spite 

 of man's best endeavors, impress its own type upon the animal. 

 In proof ()(■ til is we have only to look at some of the breeds of 

 cattle early imported into this country, and placed in circum- 

 stances so uncongenial that the most skillful care could not long 

 maintain the high state of development attained in their former 

 homes. The clinuite of the Kennebec valley makes one type of 

 Durhams, the Connecticut valley in Massachusetts another, and 

 the Winnepiseogec region still another. 



On the other hand, it .should be noticed that whenever we are 

 careful to have our efl'orts in this department of labor coincide 



