The following communication was read at the annual 

 Meeting, Wednesday, May 8, 1850, and is now printed in 

 an enlarged and revised form, as prepared by the author. 



LIST OF INFUSORIAL OBJECTS, 



found chiefly in the neighborhood of Salem, Mass., with a 

 sketch of the progress in this branch of Natural History. 



BY THOMAS COLE. 



Nearly two centuries have passed away, since the 

 microscope revealed to mankind a department of the 

 animal kingdom, consisting of bodies imperceptible to the 

 unassisted vision, but displaying, under the microscope, 

 countless multitudes of active forms, so strange and various 

 in their appearance, so beautiful, and withal so wonderful 

 in their organization, that a general curiosity was excited 

 to view this new page of nature's history, while the 

 ingenuity and skill of the most learned were exhausted in 

 forming vague theories, and absurd speculations, based 

 upon the novel and interesting spectacle. 



A slight sketch of the progress made in the investigation 

 of this branch of natural history, for which the writer is 

 chiefly indebted to Professor Ehrenberg's great work on 

 the Infusoria, will not, it is hoped, be an inappropriate 

 accompaniment to the following list of infusorial objects. 



In April of the year 1765, while the atoms and whirlpools 

 of Descartes were exciting the attention of the learned, 

 Leeuwenhoek, an eminent physician of Delft, in Holland, 

 who had busied himself with microscopical examinations 

 of the structure of plants and of the nerves of animals, and 

 who, by his skill in the construction of his microscopes, 

 his ingenuity in the preparation of his subjects, and his 

 method of applying them to the microscope, was eminently 

 qualified to make these inquiries, discovered, in a drop of 

 rain water, multitudes of briskly moving particles, and 

 thought he had found the animated primordial atoms of 



ESSEX INST. PROCEED. 5. 



