10 



LIFE, IN ITS LOWER FORMS. 



hundred thousand millions would be contained in a cubic 

 inch ; and as they are found swarming in water to such 

 a degree as that each is separated from its neighbours 

 by a space not greater than its own diameter, a single J 

 drop of such water has been estimated to contain a thou- 

 sand millions of living active beings. If we take a bunch 

 of leaves, of the common sage, for example, or a few twigs 

 of hay, and, tying them into a bundle, suspend them in a 

 jar of water, allowing the contents to remain untouched, 

 but exposed to the air, some interesting results will 

 follow. If we examine it on the second day, we shall 

 find a sort of scum covering the surface, and the whole 

 fluid becoming turbid, and slightly tinged with green. If 

 now we take, with the point of - a quill or a pin, a minute 

 drop of the liquid, and examine it with a good microscope 

 under a magnifying power of about two hundred diameters, 

 we discover the water to be swarming with animal life. 

 Immense multitudes of minute round or oval atoms are 

 present, which move rapidly with a gliding action. These 

 are animals of the genus Monas just described. Among 

 them we shall probably see other bodies still more minute, 

 resembling short lines, most of which are seen to be com- 

 posed of more or fewer bead-like bodies, united into a chain. 

 These occasionally bend themselves, "wriggle nimbly, and 

 effect a rather rapid progression in this manner. The 

 scum, or transparent pellicle, is found to be composed of 

 countless millions of these latter, congregated about as 



is about 100 feet in length. The smallest is the Twilight Monad above men- '' 

 tioned, whose dimensions are— ^-th of an inch. It is evident that tha' 

 middle term between these extremes is Jd of an inch, which is about the 

 length of the common house-fly, which may be therefore considered as aPtViXJM 

 animal of medium size in creation. - ~ , M-H"i"«*^ pr 



