394 



Microscopical Essays. 



di (covered thefe animals, and gave fome account of them in the 

 Philofophical Tranfaclions for the year 1703. There is alfo in 

 the fame volume a letter from an anonymous hand on this fubjeel:. 

 We had, however, no regular account of them, their various 

 habits, their different {pedes, or of their wonderful properties, 

 till the year 1740, when they firft engaged the attention of Mr,. 

 Trembley, to whofe affiduity and obfervations we are indebted; 

 for the knowledge of their nature and ceconomy, 



* 



Before thefe difcoveries of Mr. Trembley, Leibnitz and Boer- 

 haave, by reflections on the various gradations in the fcale of 

 animated; nature, had endeavoured to prove that there might be 

 degrees of life between the animal and the plant, and that animals 

 might be found which would propagate by flips, like plants, 

 Thefe conjectures were verified by Mr. Trembley, but not in con- 

 fequence of any preconceived ideas in favour of fuch a fuppo- 

 fition ; on the contrary,, it was only by repeated obfervations that, 

 he could deftroy his own prejudices, and join thefe wonderful; 

 beings to the animal kingdom, 



Though natural hiftory is fo fruitful in extraordinary facls, it. 

 has hitherto produced none fo Angular as. the various properties:; 

 of the different fpecies of the hydra, 



I {hall endeavour, firft, to trace the progrefs of this difcovery,. 

 in which we {hall fee with what, fage caution and accuracy Mr. 

 Trembley, and other naturalifts, examined this wonderful phe- 

 nomenon, and what accumulated evidence was judged neceflary, 

 to ejtablifh the fads.. 



We 



