202 EIGHTEENTH CENTURY. PT. in. 



heads and limbs, and that the more simple an animal is, the 

 more power it has to live and grow after it is cut in pieces. 

 These discoveries led Bonnet to make a suggestion which 

 should be remembered, because it has become of great 

 importance in the present study of natural history. He 

 asked whether it was not likely that there was a gradual de- 

 velopment or complication of the parts of the body as you 

 ascend from the lowest plant up to the highest animal, so 

 that the body of a worm, for example, could do all the work 

 necessary to keep it alive and make it grow, without the 

 help of its head, and a lizard could in the same way make a 

 new leg without much difficulty. But as the machinery grew 

 more and more complicated this would not be so easy, till 

 at last it would become impossible in the higher animals, 

 just as in a complicated machine one broken wheel will 

 upset the whole working. Bonnet wrote a book called 'The 

 Contemplation of Nature,' in which he dwelt upon this 

 subject, and tried to trace out how animal forms had become 

 gradually higher and higher, till they had arrived at man. 

 We shall see by and by how this idea occurred also to the 

 naturalist Lamarck, and how it has become the foundation 

 of a grand theory of life in the present century. Meanwhile 

 you must bear in mind that Bonnet and Spallanzani added 

 enormously to our knowledge of the lower animals and their 

 lowers of life, and together with Boerhaave, Haller, and 

 Hunter did a great deal to advance the sciences of anatomy 

 and physiology in the beginning of the eighteenth century. 



Chief Works consulted. ' Life of Haller' ' Naturalists' Library ;' 

 Brewster's 'Encyclopaedia,' arts. ' Physiology ' and 'Haller;' Lawrence's 

 'Lectures on Comparative Anatomy,' 1816 and 1848; Lawrence's 

 Translation of Blumenbach's ' System of Comparative Anatomy,' 1807; 

 Life of John Hunter' ' Naturalists' Library,' vol. x. ; Cuvier, ' Hist, 

 des Sciences Naturelles ;' Carpenter's 'Comparative Physiology;' Torn 

 Taylor's ' Leicester Square,' Appendix by 1'rofessor Owen. 



