C 42 ] 



The queftion ends with afking, <c Does the 

 " earth attract any thing inimical to vegetation? 

 " And if fo, what is it ? 



That fome earths may be more favourable to 

 vegetation than others, and that fome may be im- 

 pregnated with fteely or other poifonous matter 

 that may be inimical to vegetation, is very eafy to 

 conceive ; but that a foil, in itfelf fertile, fhould 

 attract any thing from the plants that grow in it, 

 that is inimical to future vegetation, I cannot 

 conceive. 



It is true, a very learned and ingenious member 

 (Dr. Percival) feemed to doubt, if I underftood 

 him right, whether the earth might not attract 

 fomething from the plants growing in it that might 

 be prejudicial to it; for, faid he, reafoning by 

 analogy, why is it not probable, that vegetables 

 in this refpect may fuffer like animals? For my 

 own part, I muft acknowledge, I do not know 

 that either the one or the other are fubjecl: to any 

 thing, during the different ftages of their growth, 

 that militates with or is inimical to their own 

 well-being. 



Nor can I conceive what the obfervation means, 

 unlefs it be, that the refpiration and perfpiration 



of 



