lOI- Observatio?is on Liebig's " Organic Chemistry." 



plants of mint, which grew luxuriantly. He next watered dif- 

 ferent spots in a garden with the different solutions separately, 

 and a part with common water; the grass watered with solutions 

 of jelly, sugar, and mucilage grew most vigorously ; and even 

 that watered with the solution of tannin principle, the least nu- 

 tritive of any, grew better than that watered with common water. 

 What is to become of the depositions of these substances laid 

 up as nourishment for the future embryo, in the cotyledons, 

 epicarp, mesocarp, and other coverings of the seeds, in the scales 

 and whole substance of bulbs, and around the buds in trees, if 

 these substances cannot be assimilated by plants ? In fact, if 

 these doctrines are true to their utmost extent, practical men 

 would have to learn their business anew : and, if no substances 

 are nutritive for plants till their elements are decomposed out of 

 the plant, and the whole or greater part of the carbon derived 

 from the air; if nitrogen, water, and saline bases, with small 

 quantities of earths and metals, are all that is required from the 

 soil; then, indeed, have we been labouring in vain for so many 

 years, in depositing such quantities of organic remains in the 

 shape of manures. Before receiving these doctrines, however, 

 as principles in our art, we must test them for ourselves; and, 

 while we differ from such high authority with diffidence, we 

 must carefully weigh the reasons brought forward : and, as they 

 cannot be done justice to in an essay like the present, let every 

 one interested, and they are many, have recourse to the work for 

 themselves, and read it over and over again, comparing this 

 work and others on the same subject with their own experience, 

 and the benefits resulting must be more than we can at present 

 contemplate. Many things may occur to a man in his daily 

 practice, which, if known to philosophers, would modify their 

 doctrines very considerably. 



He next proceeds to notice the erroneous opinions held by 

 some, that living beings can of themselves produce all the 

 elements required to form their constituents. That all the 

 elements are required, he proves from this fact, that dogs and 

 other animals will die, though fed on the most nutritive food, 

 unless it is varied ; and says this is a proof that the expe- 

 riments of plants attempted to be grown by sprinkling with 

 water and carbonic acid were insufficient, as the nitrogen and 

 other elements necessary were not furnished. The Carrara 

 marble on which they were grown would absorb the carbonic 

 acid, and form supercarbonate of lime ; and the sulphate of 

 baryles, and flowers of sulphur, on which also they were grown, 

 were insufficient, as the former from its specific gravity would ex- 

 clude moisture and air, and the latter would form sulphuric acid 

 with the oxygen of the air : such insufficient experiments are 

 valueless for the decision of any question, till all the requisites 



