34 



the world. Farther observations upon their motions, and 

 more especially, the discovery, in some of them, of motive 

 organs, convinced him of their animal character, and he 

 gave them the name of animalcules. In the course of his 

 experiments, Leeuwenhoek had already made an infusion 

 of pepper in water, with the hope of discovering the cause 

 of its pungency: this, after a few weeks, he found swarm- • 

 ing with animals. Others repeated the experiment, and as 

 new forms were detected, new theories respecting them 

 Avere advanced, varying with the activity of imagination in 

 the observers. " This wonderfully great world of life," 

 says Ehrenberg, " concealed from mankind, has, since its 

 discovery, been often described, under the pen of easily 

 moved and fantastical writers, as a monstrous spirit world, 

 filled with forms of which the openly visible world affords 

 no parallel, in part wonderfully, in part horribly distorted; 

 neither actually living, nor actually lifeless. Others have 

 derived them from the sportive wantonness of plastic 

 nature; even so late as the year 1820, the power of 

 charming, (^Zauberkraff) with which some of these forms 

 were supposed to be endued, was circumstantially described 

 by an otherwise meritorious writer."* 



An opinion early prevailed, that various diseases were 

 caused by minute insects filling and polluting the air, and 

 in the Philosophical Transactions of the British Royal 

 Society for 1677, a writer gravely proposes to frighten and 

 scatter these pestiferous armies by the noise of drums, 

 trumpets, and cannon, especially he recommends the cheer- 

 ful shouting of women and children for this purpose. 

 Leeuwenhoek believed that mankind and all animals origi- 

 nated in spermatozoa. A French philosopher, Periault, 

 defended the idea, derived, it is said, from Hippocrates, that 

 nothing begins to exist, but that every thing is present, and 

 is only developed and increased. Professor Sturm of 



* Infusionsthierschen Vorrede, S. 6. 



