The Microscope and Cells. 137 



149. The animalcules thus discovered were, in 

 course of time, found to comprise a great variety of 

 minute living beings, which had nothing in common 

 except their microscopic minuteness. Plants as 

 well as animals, mollusks, crustaceans, insects, and 

 worms, larvae and perfect forms, were all found to 

 have been massed indiscriminately under one vague 

 term, animalcules. Consequently, that term is now 

 taken in no specific sense ; but may be used to 

 signify all infinitesimal organic beings, of any size, 

 from the hundredth part of an inch to a minuteness 

 which the glass can scarcely distinguish, though 

 magnifying its object thousands of times. 



150. Among them there is one class which is of 

 supreme interest for the present question. We are 

 examining here the development and The uni- 

 origin of life, or the living organism cellular 

 which Darwin endeavors to transform Animalcule - 

 from one species across to another; which evolu- 

 tion, taken in a wider sense than Darwinism, en- 

 deavors to transform from the lowest and the lower 

 species up to the higher and the highest; and which 

 on the same principle should be found in the lowest 

 and simplest species only one remove, if at all re- 

 moved, from inorganic elements, from mere chem- 

 ical and physical forces. Now here among the 

 animalcules is found a class of living things which 

 are composed of single cells. The term cell desig- 

 nates the smallest integral portion of matter which 

 can exhibit life, can receive it, or can communicate 



