INFUSORIES. 157 



drawing their corpuscular food within the vortex 

 of their mouth is thus amusingly illustrated by 

 Spallanzani. As a certain species of whale, 

 says he, (sic niagnis cow porter e parva solebat) after 

 having driven shoals of herrings into a bay or 

 strait, by a blow of its tail produces a whirlpool 

 of vast extent and great rapidity, which draws 

 the herrings into its vortex ; the monster then 

 presenting its open mouth, the herrings are pre- 

 cipitated into its throat, and it is soon satiated : 

 so the carnivorous Infusories produce a vortex by 

 their tentacles, and satisfy their appetite. 



I have been more diffuse upon the history of 

 the animals whose functions in nature I am next 

 to consider, because to them in a more particular 

 manner, applies Pliny's observation with regard 

 to insects. In his tarn parvis, atque tarn nullis, 

 qiice ratio, quanta vis, quam inextricabilisperfectio! 

 In nothing is the power and wisdom of their 

 Almighty Author more signally conspicuous. Or- 

 ganization so complex, and life, and spontane- 

 ous motion, and appetite, and means to satisfy 

 it, and digestion, and nutrition, and powers of 

 reproduction in animals of such infinite minute- 

 ness ! Who can believe it ? Yet so it is, and that 

 each of these should be varied in the different 

 tribes and genera that these less than the least 

 of all the creatures that present themselves to 

 the observation of mankind, and which till within 

 a century or two were not suspected to exist, should 



