194 LETTER LXf. 



guage, is so frequently made the emblem of invading 

 armies, and, of extensive desolation. 



The hydra, or fresh water polypus, which was first 

 noticed by Mr. Tremblay, A. 1). 1741, may serve, 

 my dear Sir, to give you a general idea of zoophytes ; 

 an order of compound animals furnished with a kind 

 of flowers, and having a vegetable root and stem. 

 This order, which naturalists have divided into fifteen 

 genera, seems to form that link in the chain of being 

 which connects the animal and vegetable kingdoms. 



The hydra was at iir.st considered as a mere plant ; 

 but it was soon discovered to be a sensitive being, 

 and yet capable of propagation by slips. Of this ge- 

 nus various species are found in different situations, 

 in ditches and pools of stagnant water ; but all of 

 them possess the property of reproduction in what- 

 ever manner they are divided. If cut into three 

 parts, each puts out a head from one, and a tail from 

 the other, so as to become three distinct animals, all 

 performing the functions of their species, and exhi- 

 biting perfect copies of their original. Although the 

 different genera and species of insects which our eyes 

 can discover, are, as already observed, numerous be- 

 yond calculation ; and in their formation, their co- 

 lours, and their habits, various beyond all that fancy 

 itself could conceive, yet there are multitudes of 

 others which cannot be perceived without the aid of 

 the microscope. There is also not the least reason to 

 doubt but there are gradations of existence below the 

 smallest animalcules, which our nicest instruments 

 have not brought to light. We have already been 

 able to discover myriads of living creatures in the 

 least drop of the purest water; and it seems to be a 

 rational presumption to infer, that he who has filled 

 the immensity of space with habitable matter, .with 

 suns and worlds innumerable, has also peopled every 

 part of that matter with appropriate inhabitants, 

 although too minute to be perceived by any appara- 

 tus yet invented. The supposition is not unworthy of 

 the Creator of the Universe, and all the analogic* 



