AND THE LOWER ANIMALS. 137 



who seek them, placed Trembley upon a new path of 

 study. He placed in a glass vessel a quantity of 

 ditch water, whose surface was covered with those 

 little isolated plants which consist of two spread- 

 ing green leaves and some fine rootlets, and which 

 are commonly known as " duck-weed." After a while 

 he perceived a number of small bodies of a beautiful 

 green hue attached to the transparent walls of the 

 bowl, and which gradually changed their form and 

 proportions, sometimes remaining perfectly motion- 

 less, and at others travelling slowly along the glass. 

 When completely elongated, their bodies were like 

 hollow cylinders, five or six lines long, whose free 

 extremity exhibited a central orifice, and was sur- 

 rounded by a variable number of retractile tentacles, 

 moveable in every direction. On touching them, 

 these tentacles were rapidly drawn in, seeming to dis- 

 appear altogether, and the cylinder was reduced to 

 the form of a conical projection, hardly one line in 

 length. 



Trembley was for a long while ignorant of the real 

 nature of these curious bodies. Were they animals ? 

 or were they plants 'endowed with the power of sensa- 

 tion ? The form and colour were those of a plant ; 

 but on the other hand these bodies moved along some- 

 times indeed very slowly, but at others by making- a 

 series of bounds, by no means unlike those of a 

 mountebank. To solve this problem, he cut one of 

 these enigmatical beings in two, and in forty-eight 

 hours after, each half had become a perfect organism 

 like the original. When, it was divided into twenty, 

 thirty, and even fifty portions, there were as many 

 perfect individuals produced. At the same time 



