Cfmnges of Plants^ and Animals. 359 



husbandry are better understood. But here, where the 

 wildness of nature is constantly in view, tHe attention of 

 our farmers being called to her operations, will produce 

 conviction, sooner than elaborate discussion, or technical 

 example. 



In my endeavour to shew the necessity of changing 

 crops, and the utilit}^ of also changing the locality of ani- 

 mals (the former well known, in Europe, to be essential, 

 and the latter thought to be so by many) I mentioned, 

 in our first volume, a number of facts ^within my own 

 knowledge, and procured testimony from very respec- 

 table sources, corroborating those facts, as to changes 

 in natural products of timber and plants, which are un- 

 deniably proved. I have known them to be true, from 

 my youth. I think them very strong indications of the 

 absolute necessity of changes of products, in agricultu- 

 ral operations. I also conceive, that great support is 

 afforded to the opinion, that change of locality is neces- 

 sary, to preserve domestic animals from deterioration, 

 by the facts, in frequent proof, that when one race of wild 

 animals, migrates, or becomes extinct, a different race, 

 or races (in obedience to a natural propensity to change) 

 is, or are, found in the haunts of those precedently in 

 the occupation of them. I had intended to have prose- 

 cuted this inquiry, and to accumulate a multitude of 

 facts on this subject ; and I may yet, at a time of leisure, 

 perform my promise. Mean time, I hold it a duty I owe 

 to myself, to say, that I never have had the most distant 

 idea of bringing into view these, or any other facts, to 

 support hypothesis, or theory, of any kind. On the 

 contrary, any candid reader will see, that I cautiously 

 avoid all such vain and unnecessary speculations. My 



