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. Wo are compelled here to recog- 
nise the Great First Causo, and to say, “ In Him we live, 
and move, and have our being.” 
The researches of modem 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, tho 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 eyo, and containing within it a smaller cell, 
called the nucleus, which again contains a still more mi- 
nute granule, called the nucleolus, orlittle 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, 
