2 GENERAL HISTORY OF 



" In the clearest waters, and also in the troubled, strongly 

 acid, and salt fluids of the various zones of the earth ; in 

 springs, rivers, lakes, and seas ; in the internal moisture of 

 living plants and animal bodies, and, probably, at times, 

 carried about in the vapour and dust of the whole atmo- 

 sphere of the earth, exists a world, by the common senses 

 of mankind unperceived, of very minute living beings, 

 which have been called, for the last seventy years, 

 INFUSORIA. In the ordinary pursuits of life, this myste- 

 rious and infinite kingdom of living creatures is passed by 

 without our knowledge of, or interest in, its wonders. 

 But, to the quiet observer, how astonishing do these 

 become, when he brings to his aid those optical powers by 

 which his faculty of vision is so much strengthened. In 

 every drop of dirty stagnant water, we are generally, if not 

 always, able to perceive, by means of the microscope, 

 moving bodies, of from 1-1 150th to 1 -25,000th of an inch 

 in diameter; and which often live packed together so 

 closely, that the space between each individual scarcely 

 equals that of their diameter/' 



The wisdom and goodness of Providence have endowed 

 these living creatures with all that can be needed for their 

 happy existence. A reference to the drawings, generally, 

 will afford some idea of their beautiful and varied forms. 

 What, for instance, can be more admirable in structure 

 than the Infusoria of the family Volvocina ? (See Plate I. 

 figs. 34 to 57.) In what class of animals are its members 

 so curiously and so symetrically associated together ? In 

 the Volvocina, innumerable beings are colonized within a 

 simple, delicate, crystal-like shell, whose form, sometimes 

 spherical, at others quadrangular, presents us with 



