22 VIEWS OF THE MICROSCOPIC WORLD. 



young matured, that from a single animaloule millions will proceed in the course 

 of a few "days. Dr. Ehrenberg kept one of this class of Infusoria for eighteen 

 days in a separate vessel of water ; during this interval it lai'd four eggs a day, 

 and. the young, when two days old, laid the same number ; so that, continuing 

 to multiply at this rate, it was found that under favorable circumstances, the off- 

 spring of a single creature would amount, in the course of ten days, to one 

 million ; in eleven, to four millions ; and in twelve days, to sixteen millions. 

 This is the greatest increase that has actually been determined by experiment. 

 In the other class of Infusoria, the Polygastrica, the fecundity is much greater, 

 inasmuch as they are endowed with more varied powers of reproduction. A 

 single animalcule belonging to one of the larger kinds is known to separate into 

 eight, in the course of a day, by self-division ; so that, multiplying at this rate 

 for the space of ten days, it would increase to more than one hundred and fifty 

 millions individuals. It likewise propagates from eggs, which are seen in clusters 

 like the spawn of fishes ; and also by buds, that sprout from the sides of its body. 

 When all these facts are taken into view, it is evident, that the vast number of 

 living beings, which in a few days spring from a creature as prolific as this, is 

 utterly beyond our powers of appreciation. It has been affirmed by naturalists, 

 that such is the amazing fecundity of the box-chain animalcule (Gallionella), 

 that in twenty-four hours a single individual will increase to the number of one 

 hundred and forty million millions, (140,000,000,000,000.) 



LIFE AND RESUSCITATION. Infusorial animalcules live but for<ashort period, 

 for although the duration of their life varies in different kinds, it extends only 

 from a few hours to several weeks. Wheel animalcules have been seen in the 

 enjoyment of their existence twenty-three days after their birth. The death of 

 Infusoria is usually sudden, and in the larger species is attended with spasms. 

 The soft parts rapidly decompose after death, and all the curious and elaborate 

 organs of these singular beings entirely vanish ; nothing appearing to remain 

 except the transparent flinty shells in which many kinds of the Infusoria are en- 

 cased. But in numerous instances, this death is but apparent ; the decay of the 

 body does not take place, and in the minute speck, that lies before us like an 

 atom of inanimate dust, the mysterious principle of life is still in existence. The 

 creature may remain motionless for months, and even years ; but when it is again 

 subjected to influences favorable to its resuscitation, it awakens from its torpor, 

 and life, with all its former energies, is once more fully displayed. 



This surprising phenomenon is supported by undoubted proof. When the 

 water containing a wheel-animalcule evaporates, the creature apparently expires, 

 becomes dry and hard, and may be preserved in this state for years, if buried in 

 sand. When placed in water in this condition, it will revive in a few minutes, and 

 soon swim about with its wonted activity. In 1701 Leuwenhoeck observed this 

 fact in wheel animalcules, and revived some specimens after keeping them dry for 

 twenty-one months. Baker obtained the same result after a longer time, and 

 Prof. Owen was present at the resuscitation of an animalcule after it had lain 



