314 PRINCIPLES OF GARDENING. [CH. IX. 



apple and pear get into an ii'ony red, gravelly 

 subsoil, al-ways causes canker to supervene. In the 

 neighboui'liood of copper-smelting furnaces not only 

 are cattle subjected to swollen joints, and other 

 unusual diseases, causing decrepitude and death, but 

 the plants also around are subject to sudden visit- 

 ations — to irregular growths, and to unwarned 

 destruction : and a crop once vigorous ^^•ill sud- 

 denly wither as if swept over by a blast. There is 

 no doubt of this arising from the salts of copper 

 which impregnate the soil irregularly as the winds 

 may have borne them sublimed from the furnaces, 

 and the experiments of Sennebier have she^vn, that 

 of all salts those of copper are the most fatal to 

 plants. 



That they can be poisoned, and by many of those 

 substances, narcotic as well as corrosive, which are 

 fatal to animals, has been she^ii by the experi- 

 ments of M. F. Marcet. The metallic poisons being 

 absorbed are conveyed to the different parts of the 

 plant, and alter or destroy its tissue. The vege^ 

 table poisons, such as opium, stiychnia, prussic 

 acid, belladonna, alcohol, and oxalic acid, which act 

 fatally upon the nenous system of animals, also 

 cause the death of plants. Does not this fa- 

 vour the opinion of those who believe that there 

 is something in plants analogous to the nerves in 

 animals? is the natui'ally suggested inquiiy made 



