200 EIGHTEENTH CENTURY. pt. hi. 



he could, and showing how it suited the wants of the various 

 animals. His museum cost him an immense amount of labour, 

 and more than 70,000/. in money ; when he died, in 1793, it 

 was bought by the English Government for 15,000/. and 

 placed in the London College of Surgeons, and for the last 

 eighty years many a London student of physiology has had 

 occasion to be thankful to the rough and uneducated John 

 Hunter for the laborious and careful work he did, and the 

 magnificent collection he left behind him. 



Experiments upon Animals by Bonnet and Spallanzani. 

 — ^While Haller and Hunter by their dissections were adding 

 greatly to our knowledge of the structure of animals, two 

 famous naturalists in Switzerland and Italy were bringing to 

 light some extremely curious and interesting facts about their 

 growth. 



The first of these, named Charles Bonnet, was born at 

 Geneva in 1720, and died in 1793. He had a great love of 

 natural history, and when he was twenty years of age he 

 wrote a paper upon aphides^ or plant-lice, which was so re- 

 markable that the French Academy of Sciences at once 

 elected him one of their corresponding members. He 

 also made some v^ry interesting experiments upon plants, 

 showing that they have the power of seeking out for them- 

 selves what is necessary for their growth. We all know that 

 plants grow towards the light, and if kept in a dark room 

 will seek out even a crack through which the light comes. 

 But Bonnet proved that they will do much more than this, 

 for he found that if he twisted the branch of a tree so as to 

 turn the leaves bottom upwards, in a little time each leaf 

 turned right round on its stalk so as to get back into its 

 natural position ; while on the other hand, if he hung a wet 

 sponge over a leaf, the leaf would turn its under side up- 



