562 ' SHAVINGS EXAMINED MICROSCOPICALLY. 
organisms that puzzle and delight the students of atomies, 
and which are grouped under the great collective head of the 
Protophyta, are constructed after the same general plan, and 
consist of the same chemical substances, congregated to- 
gether after similar types, varying only in degrees of com- 
plexity. And what is an equally, if not more remarkable 
fact, those substances which go to make up the bulk of the 
vegetable organism are found also in the animal, constituting 
the elementary components of its body likewise. 
However it is not our intention, at the present time, to 
enter into the consideration of the chemical constitution of 
vegetable tissues; interesting as that branch of vegetable 
physiology is, we must forbear, and, assisted by the micro- 
scope, proceed to the examination of those tissues them- 
selves. The general structure of all plants consists of a 
substance known to chemists under the name of cellulose, 
the wall-matter of cells, so to speak; cells being the most 
important part of plants, as we shall see presently. It is 
this cellulose that we are so well acquainted with under so 
many different forms and names and constituting vegetable 
fibre, bark, the great mass and harder portions of all leaves; 
flowers, fruit and stems; and, although in special cases we 
find it somewhat modified, it is always to be recognized from a 
its possessing certain unmistakable characteristics, familiar 
to all in the substance of paper, and, therefore, of course, d 
in the linen or cotton, the wood or the straw from which the € 
paper was made, so that we say that about all the paper we : 
see is composed of cellulose in almost a pure condition, 
there being but little used which is manufactured from 
animal tissues, such as wool and silk. The rice-paper of 
the Chinese is not, as is generally supposed, made of rice, 
but of the light and porous pith of a plant which has been 
cut in the form of a broad strip, around and around the mass 
: of the tissue, as is plainly seen when a small piece is exam- 
~ ined by means of a magnifying glass, when the little cells or 
cavities which made up the pith are very evident. Woody 

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