28 



INFUSORIA. 



animal, originally one flesh, proceeds to divorce itself 

 into twoo 



Fig. 15.— figure of a-orticelLwS. 



This mode of propagation, in Avhich multiplication 

 and division go hand in hand, is amazingly pro- 

 ductive : and, indeed, far surpasses in fertility any 

 other with which we are acquainted. Every school- 

 boy is familiar with the celebrated problem about 

 the nails in a horse's shoe, or the squares of a chess- 

 board, where the results attainable by duplicative 

 multiplication soon pass ordinary numerical ex- 

 pressions. Let any of our readers try the same 

 ])roblem with one of these animalcules. An in- 

 dividual, if well supplied Avith food, has been observed 

 to divide at least once in twenty-four hours. So that 

 in a fortnight, allowing the product of each division 

 to multiply at the same rate, sixteen thousand three 

 hundred and eighty-four would be produced from the 

 same stock, and in four weeks tAvo hundred and 

 sixty-eight millions, four hundred and thirty-five 

 thousand four hundred and fifty-six, would be the 

 astounding progeny derived from a single animalcule. 



