20 



LIFE, IN ITS LOWER FORMS. 



found in large quantities resembling flour in appearance. 

 The natives of these districts have long been in the habit 

 of collecting this, and of using it, under the name of 

 bergmehl, or mountain-meal, as an article of food, This, 

 also, the microscope reveals to be composed of the remains 

 of incalculable millions of shelled Infusoria. 



Some interesting examples of a protecting case of dif- 

 ferent structure are found in the family Tintinnidce. They 

 are animals allied to the Vorticella, but inhabiting a 

 transparent tube, open at the top, of a gelatinous or mem- 

 branous texture. This case is affixed to the stems of 

 water-plants, sometimes by its base, when it is erect, at 

 others prostrate, adhering by its side, and occasionally 

 placed at the tip of a footstalk, like a tiny handbell turned 

 upside down. The animalcule protrudes to a consider- 

 able distance from the margin of its glassy cell, unfolding 

 a ciliated mouth like that described in the preceding 

 chapter ; but on the least disturbance it shrinks, a little 

 shapeless ball, down to the very bottom of its tube. 

 Sometimes two animals dwell in the same tube, and their 

 amicable movements are viewed with ease through the 

 transparent walls of their miniature crystal palace. 



Those who have never looked through a microscope 

 can scarcely form an idea of the beauty of these little 

 animals. Engravings of many of them, and technical 

 descriptions, are, indeed, to be found in published works ; 

 but of their brilliant transparency, their high refractive 

 power, resembling that of flint-glass, their sudden ana 

 sprightly motions, their general elegance and delicacy, and 

 the appearance of intelligence which they display, neither 

 books nor engravings will give any adequate conception. 



