No. 105.] 211 



sary that he should understand the nature of acclimation, the influ- 

 ence of heatj cold, moisture, and fertility, on the germination, and 

 action of the roots, stems, leaves, and various other parts of plants. 

 Such knowledge would be also highly advantageous to the enterpris- 

 ing agriculturist, whose object, aside from the profit, is to introduce 

 new vegetable productions for general culture, and who should there- 

 fore understand the effect of removal to an unlike climate and soil. 



But this science often becomes very useful to the common farmer. 

 A knowledge of physiology, and of the enormous quantity of moisture 

 which plants perspire insensibly from the leaves, would have wholly 

 prevented the very common and pernicious error, that weeds pre- 

 served moisture in the earth, and shade contiguous plants from the 

 effect of drought, while in fact every weed is an outlet through which 

 moisture as well as nourishment is rapidly drained from the soil. An 

 acquaintance with the principles of botany would have prevented the 

 prevalence of the equally pernicious notion, that the weed so com- 

 mon in wheat, termed chess, could ever be transmuted to wheat, a 

 plant not only of a different species, beyond the boundary of which, 

 a plant by no change ever passes, but is also of a different genus. 

 A knowledge of the fact, that no root of a plant can long remain 

 alive, which in a growing state, when deprived of its breathing ap- 

 paratus, the leaves, would have prevented the wild attempt practised 

 some years ago, of endeavoring to destroy patches of canada thistles, 

 by carefully digging up every fibre of the roots from a depth of seve- 

 ral feet ; while a simple, obvious, and efficacious remedy consisted 

 in merely starving the roots, by cutting off unremittingly the supply 

 from the leaves for a proper length of time. Were the vital impor- 

 tance of the leaves to the health and perfection of the seeds of plants 

 properly understood, the practice of "topping" corn would never 

 have been resorted to. In numerous other cases, this science serves 

 to throw light on operations of culture and to assist correct practices. 

 I An intimate and important connexion exists between agriculture, 

 and chemistry combined with vegetable physiology. In some cases, 

 considerable accuracy of reasoning, and certainty of application may 

 exist ; in others, all seems as yet involved in uncertainty. The 

 triple relations of the analysis of plants, of soils, and of manures, 

 and the determination of the constituents of each, promise, perhaps, 

 more important results than any other department. 



