INFUSORIAL ANIMALCULES. 3 



eager to test the accuracy of these astounding assertions, or that 

 a great impetus should thus have heen given to the general 

 study of the minute forms of life with which the waters abound. 

 But many years still passed before this branch of study was at all 

 systematically pursued : and although towards the close of the 

 last, and early in the present, century, it attracted to itself a con- 

 siderable number of able and zealous investigators, it was not 

 until almost our own day that it took its place as a recognized 

 and important department of natural science. 



It was for many years customary to speak of these living 

 atoms indiscriminately as the Infusoria, or as Infusorial Ani- 

 malcules, from the circumstance that they were originally 

 detected in infusions of vegetable substances. More careful 

 investigation, however, has shown that the organisms thus 

 hastily associated together differ widely from each other; and 

 that many of the tribes are, on the whole, more nearly related 

 to the vegetable than to the animal world. Moreover, amongst 

 those whose animal nature is perfectly obvious, the differences 

 which have been observed as to organization are so great, that 

 while roost of the number take rank with the very humblest 

 forms of sentient beings, others, again, present a much more 

 complicated structure, and are now properly classed with the 

 higher divisions of the invertebrate animals, minute though they 

 be, and, in this respect, true animalcules. It would seem, indeed, 

 that the earlier investigators of this invisible world of organic 

 life were so elated with the remarkable discovery they had in 

 charge, that they were disposed to regard everything belonging 

 to it as perfectly unique, quite separate and distinct from all 

 that had previously been known. No matter, therefore, what the 

 objects were that came within the field of their microscopes the 

 eggs and larva? of insects, the germs of embryo polyps, the spores 

 of fungi, and many different forms of mature plants, together 

 with other matters of a still more heterogeneous character all 

 were alike set down as being organisms of the. same general cha- 

 racter, and regarded as equally belonging to this newly discovered 

 world of Infusorial Animalcules. 



It affords a curious illustration of the union of great powers 

 and special aptitude for delicate research with unaccountable 

 proneness to deception, that Ehrenberg, the great microscopist of 

 Berlin, and for many years the almost undisputed authority on, 



