POISONOUS PLANTS AND ANIMALS 103 



There is, over and above these special cases of fish 

 foods which are tolerated by some and are poison to 

 others, a whole series of fishes which cannot be eaten by 

 any one without serious poisoning being the result, even 

 when the fish are carefully cooked. Happily, these 

 fishes are rarely, if ever, caught on our own coasts. 

 They produce, when even small bits are eaten, violent 

 irritation of the intestine, and death, the symptoms 

 resembling in many respects those of cholera. The 

 curious bright-coloured, beaked fish of tropical seas and 

 coral reefs, with two or four large front teeth and 

 spherical spine-covered bodies, and the trigger fish of 

 the same regions, are the chief of these poisonous fish. 

 But there is a true anchovy on the coast of Japan, and a 

 small herring in the West Indies, and a goby on the 

 Indian coast (Pondicherry), all of which are deadly 

 poison even when cooked ; and there are many others. 

 So one has to be careful about fish-eating in the remoter 

 parts of the world. The poisons of these fish with 

 poisonous flesh have not been carefully studied, but they 

 seem to resemble chemically the poisons produced by 

 certain putrefactive microbes. 



Let us now revert to the more special subject of 

 poisonous stings. Every one knows that although it is 

 unpleasant to be pricked by the little spines on the leaf 

 of a thistle, it is not the same unpleasantness as being 

 " stung " by a nettle. There is no poison in the thistle. 

 The hairs which beset the leaves of the common nettle 

 are firm, but brittle and hollow ; they break off in the 

 skin, and a poison exudes from their interior. Under 

 the microscope and it is quite easy to examine it with 

 a high power the hollow nettle hair is seen to be partly 

 occupied by living protoplasm a transparent, viscid 

 substance which shows an active streaming movement, 

 and has embedded in it a dense kernel or nucleus (see 



