Marvels of Pond-Life. 1 15 



of the brain of an ant make it the recipient of a liiglicr 

 instinct, or give its possessor greater capacities for 

 dealing with new and unexpected diniculties than are 

 possessed by most other insects, and if any reader has 

 a marine aquarium, and will make a few exi)erinients 

 in taming prawns, and watching their proceedings, lie 

 will discover symptoms of intelligence beyond what the 

 structure of the creature would have led him to expect. 



Animals usually possess some one leading cliarac- 

 teristic to which their general structure is subordinated. 

 Man stands alone in having tlie whole of his organiza- 

 tion conformed to the demands of a thinking, ruling 

 •brain. To pass at once to the other extreme, we 

 observe in the lower infusoria a restless locomotion, 

 probably subservient to respiration, but utterly in- 

 consistent with a well developed life of relation, or 

 with manifestations of thought. The life of an ani- 

 malcule may be summed up as a brief and restricted, 

 but vigorous organic energy, and if the amount of 

 change which a single creature can make in the ex- 

 ternal world, is inconceivably small, the labours of the 

 entire race alter the conditions of a prodigious amount 

 of matter. Microscopic vegetable life is an important 

 agent in purifying water from the taint of decomposing 

 organisms. By evolving oxygen it brings putrescent 

 particles under the iniiuencc of a species of conil)ustion, 

 which, though slow, is as effectual as tliat which a 

 furnace could accomplish. In this way minute moulds 

 burn up decaying wood. 



Microscopic animal life helps the regenerative pro- 

 cess; and, together with the minute vcgetabU' life, 



10 



