142 THE STORY-BOOK OF SCIENCE 



fly for which he thoughtlessly thrust his hand into 

 the tuft of nettles is called the Vanessa lo. Its 

 caterpillar is velvety black with white spots. It 

 also bristles with thorns. It does not make a co- 

 coon. Its chrysalis, ornamented with bands that 

 shine like gold, is suspended in the air by the end 

 of its tail. The caterpillar lives on the nettle, of 

 which it eats the leaves, notwithstanding their 

 venomous bristles. " 



"In browsing on the venomous plant, how does 

 the caterpillar manage so as not to poison itself ?" 

 Claire inquired. 



"My dear child, you confound venomous with 

 poisonous. Venomous is said of a substance that, 

 introduced into the blood by any kind of a wound, 

 causes injury in the manner of the viper's venom. 

 Poisonous is said of a substance that, swallowed 

 or introduced into the stomach, may cause death. 

 Fatal drugs are poisonous: they kill if eaten or 

 drunk. The liquid that flows from the viper 's fangs 

 and the scorpion's sting is venomous: it kills when 

 it mixes with the blood ; but it is not poisonous, for 

 it can be swallowed with impunity. It is the same 

 with the nettle's venom. So Mother Ambroisine 

 gives the poultry chopped nettles, and the caterpillar 

 of the Vanessa feeds without danger on the plant 

 which, a little while ago, made Emile cry with pain. 

 Of venomous plants we have in our country only 

 nettles; but we have many poisonous plants that, 

 when eaten, cause illness and even death. I must 

 certainly tell you about them some day, so as to 

 teach you to avoid them. 



