28 



NATURAL HISTORY 



fusions that many millions in a single drop may be 

 taken up on the head of a feeding pin*. In swimming 

 they do not move with rapidity, but as they are seldom 

 entirely at rest, it is difficult to observe them with 

 precision ; they are most distinctly seen when the drop 

 has nearly evaporated. The instrument I have viewed 

 them under was an aplanatic engiscope, with deep 

 objectives of l-6th to l-12th of an inch focus; if 

 this cannot be procured, doublet magnifiers, or single 

 lenses of l-60th to 1-1 00th of an inch focus, are prefer- 

 able to the common compound. In the solar achromatic, 

 in the confines of the light, young animalcules have been 

 discerned much smaller than l-24,000th of an inch, and 

 it is probable that more perfect instruments would ex- 

 hibit even smaller animated beings ; to observe these, 

 howev-er, it is necessary to have finely-divided opaque- 

 coloured matter in the fluid. 



It may be doubted whether any reasoning being, who 

 has seen these minute living atoms, can contemplate them 

 without the most positive conviction that they are the 

 work of an all-wise Creator, and doubtless intended by 

 Him for some useful purpose in the economy of nature ; 

 for if w^e consider the almost countless numbers that 

 exist in the small space of only an inch, whither will our 

 imagination lead us when we think on the myriads that 

 would occupy the bulk of a single Elephant ! 



If we take some of the largest of these animalcules, 



* See " Microscopic Cabinet," page 235. 



