CELLS. 



3 



living being ; and what that mighty principle is, the loss 

 of which has wrought such a change, alike eludes research 

 and baffles conjecture. We are compelled here to recog- 

 nise the Great First Cause, and to say, " In Him we live, 

 and move, and have our being. 3 ' 



The researches of modern science, however, aided by the 

 inventions which it has brought into requisition, though 

 they have been unable to throw a single ray of light on the 

 nature of Life itself, have yet done much to make us 

 familiar with its phenomena. The microscope, in par- 

 ticular, has opened to our inquiry what we may call a 

 world of life, under phases and forms as strange and sur- 

 prising as they were before unknown. It has enabled us 

 also to separate and analyse the various substances or 

 tissues of which the highest forms of animate being are 

 composed, and to resolve them into their first elements. 

 Numerous and diverse as are these substances — bone, 

 cartilage, sinew, nerve, muscle, hair, the teeth, the nails 

 of the hand, the transparent lens of the eye, — all are 

 reducible to one kind of structure. This structure is a 

 cell. All organic substances are made up of cells. The pri- 

 mary organic cell is a minute, pellucid, globule, invisible 

 to the naked eye, and containing within it a smaller cell, 

 called the nucleus, which again contains a still more mi- 

 nutegranule, called the nucleolus, or little nucleus. Even the 

 highest animals, in the early development of the embryo, 

 are composed entirely of nucleated cells, which afterwards 

 assume the forms peculiar to the various tissues. In the 

 lowest classes of animals, their more simple bodies consist 

 almost entirely of cells of this kind. If we take a minute 

 portion of the gelatinous flesh of a medusa or a zoophyte, 



