46 On Plants absorbing coloured infusions by their roots. 



earth, will destroy as with a stroke of lightening, those same plants 

 when they are exposed to its immediate agency. 



I argue th enfrom the results which I have detailed, first, that, 

 coloured, or chemical infusions and liquids will not enter into the 

 vascular or cellular system, provided the plant, either by its own 

 vital energy, or by the decomposing power of the soil, remain in a 

 state of health and power to develope its new parts ; therefore 

 that, no precise knowledge of the sap vessels can be obtained by 

 such artificial means as have usually been employed. Secondly, 

 That where a plant ceases to grow, turns yellow, and evidently 

 becomes sickly, it may absorb unnatural aliment; not however 

 through its regular organs of absorption, but by diseased action 

 through, in all probability, abraded surfaces; hence then, while 

 vital energy acts, and health remains unimpaired, true sap alone 

 is generated. The office of soil is to reduce all substances to its 

 own nature; and this it speedily effects through the stimulus of 

 living vegetation. If, however, substances foreign to soil super- 

 abound, injury, as abrasion, or corrosion is, I apprehend induced ; 

 diseased action and absorption supervene, the plant becomes 

 poisoned, sickens and perishes. 



