OF ANIMALCULES. 17 



an amazing extent^ that it would be utterly impossible to 

 compute those in a single drop of the fluid. After this, 

 again, they will begin to diminish in numbers, and I 

 have generally observed them supplanted by others of a 

 larger species and more perfect organization ; such as 

 the Cyclidia, Paramesia, Kolpodae, &c. It is worthy of 

 remark here, however, that in their production they do 

 not pursue any regular order, even in similar infusions. 

 If the vessel be large, and the circumstances under 

 which it is placed sufficiently favourable, a still higher 

 description of animalcules will succeed, viz. the Vor- 

 ticella, and, lastly, the Brachioni ; and thus a single in- 

 fusion will repay for the little trouble of making it, with 

 a great variety of species. Water in which flour has 

 been steeped will be found to abound also with animal- 

 cules : and it is remarked by G. Leach, Esq. that the 

 leaden troughs, constantly appropriated for birds to drink 

 out of, contain several descriptions of them, and more 

 especially those of the wheel genus. In ponds, too, 

 especially in the shallow parts, near their edges, and in 

 the immediate vicinity of water-plants, prodigious quan- 

 tities of all kinds may be easily procured ; so that pos- 

 sessing as we do such myriads of them all around us, that 

 they impregnate almost every thing that we eat and 

 drink, touch and breathe, an anxiety to know more 

 about them, and the eff*ects they produce, cannot but be 

 regarded as rational and laudable. 



It would be exceedingly difficult, if not impossible, to 



