INFUSORIA. 413 



for the motion of the cilia becomes more and more languid, 

 and the creatures die before the water is dry. They not 

 only die,hutva?iish ; so that, — where there were scores, so 

 close that in moving they indented each other's sides and 

 crawled over one another, — if we look away for a few 

 minutes, and again look, we see nothing but a few loose 

 granules. This puzzled me, till I watched some dying, 

 and I found that each one burst and, as it were, dissolved. 

 The cilia moved up to the very last moment, especially the 

 strong ones in front, until, from some point in the outline, 

 the edge became invisible, and immediately the animal 

 became shapeless, and from the part which had dissolved 

 the interior parts seemed to escape, or rather the skin, so 

 to speak, seemed to dissolve, leaving only the loose viscera. 

 From the midst of these then pressed, as if by the force 

 of an elastic fluid within, several vesicles of a pearly 

 appearance, varying in number and size, and then the 

 whole became evanescent. 



You will have observed that the admixture of carmine 

 to the water, while the animalcules were active, shows the 

 direction of the ciliary motion with great distinctness. 

 The particles form two eddies, one on each side of the 

 front, which meet in the centre in a strong current, and 

 pass off behind the mouth on each side. We do not 

 perceive that any of them swallow the particles of 

 carmine, for the internal vessels remain colourless. 



I have found that if a drop of water containing these 

 animals be placed on a slip of glass exposed to the open 

 air, they do not burst as the water dries away, but dry 

 flat on the glass, their bodies broader but shorter than 

 when alive, and quite entire. Their cilia are then very 

 manifest. On being again wetted, though after only 

 a few minutes' desiccation, I have never been able to 

 revive them, nor any other Infusoria in like circum- 

 stances, notwithstanding what is stated in books. 



Here is another species in equally amazing profusion, 



