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 tills, 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. 
Somo interesting examples of a protecting case of dif- 
ferent structure ai-e found in the family Tmtinnichs. 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 animalculo protrudes to a consider- 
able distance from the margin of its glassy coll, 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 mioroscope 
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 and 
sprightly motions, their general elegance and delicacy, and 
the appearance of intelligence which they display, neither 
books nor engravings will give any adequate conception. 
