316 QUALITIES 



for all the productions of nature are individuals ; and, 

 though there be varieties in the successions of indi- 

 viduals, sometimes produced by circumstances which 

 we can imitate and sometimes not, the succession is in 

 the species that is, the plant bears more resemblance 

 to the immediate parent plant than to a plant of any 

 other kind) there are often very contradictory or 

 opposite properties in them. Thus, the Jatropha 

 manihot, which has been mentioned as forming the 

 bread of the natives of Central America, not only 

 belongs to an exceedingly poisonous family (Euphor- 

 biacea),but is, when raw, a deadly poison. The 

 various spurges, and other members of the family 

 which are found in England, are all acrid ; and their 

 milky juice, which blisters very delicate skin, is used 

 to remove warts and other callosities. Some plants 

 of that family yield valuable, or at all events pow- 

 erful medicines, such as castor and croton oils ; but 

 some of them act too powerfully for being used even 

 in the smallest quantity. The perennial mercury, 

 or " dog's cabbage," said to be so called from dogs 

 preferring it to any other plant, when they physic 

 themselves with green vegetables, and which grows 

 in the woods of some parts of Britain, the male 

 plants usually in one patch and the females in an- 

 other, is eatable, though still aperient when well- 

 boiled, but poisonous raw, or even roasted or fried. 

 That property is so general, that when experiments 

 are made as to whether new vegetables may or may 

 not be used as food, the safest plan is to boil them, 

 and throw away the water in which they are boiled. 

 One of the most curious orders of plants in that 

 respect is the fig tribe, or, as they are sometimes 

 called, from comprehending the different species of 

 bread-fruit, the bread-fruit tribe. Of fruits well known 

 in England, the fig and the mulberry belong to that 

 family ; and though the fruit of these be eatable, the 

 juice of both, that of the fig especially, is a poison. 

 This family are very numerous in the warm countries, 



