POISON OF PLANTS. 343 



different from both mechanical and chemical re- 

 sults. We cannot repeat one of them, and there- 

 fore we can never safely say that any one of them 

 has a property, unless that property has actually 

 been discovered in it. 



Still the poison, or the other active matter that 

 may be in the plant, is well worthy of our study ; 

 because, generally speaking, it is in the plant 

 itself, and not in the food of the plant. In what- 

 ever part of the plant it may ultimately be found, 

 whether in the root, as in the jatropha ; in the 

 juice, as in the sperges ; in follicles, with prickles 

 on the bark, as in the nettle tribe ; in the oil of 

 the seeds, as in the violen ; or in their substances, 

 as in nux vomica it is always found in one part 

 of the plant when in the embryo state. That part 

 is the embryo itself, when the habit of the plant 

 is such that that is considerably developed in 

 the seed. When that is not the case, the most 

 virulent property is in the tunics or coats ; and 

 that is the case also with roots, and it is the same 

 whatever may be the nature of the poison. In 

 the pulp of the peach there is not a trace of that 

 prussic acid which scents the flower and flavours 

 the kernel ; the pulp of the yew-berry is harmless, 

 and probably so are the cotyledons, if the embryo 

 were removed, as that is the case with many of 

 the seeds of theEuphorbiacea, and other tribes. In 

 the potatoe, the poisonous quality, which, though 

 not very strong, is still a poison, is chiefly in the 

 tunic or skin, or immediately under it ; and the 

 same is, in all probability, the case in jatropha. 

 Even the common turnip, which belongs to an 

 order of which probably none are poisonous, 



