‘8 INTRODUCTION. 
re 
second kind of change that appears to be the cause of ee 
death. ve x 
If we examine . the various : living bodies more closely, we 
find they possess a common structure, which a little reflection 
“soon causes us to perceive is essential to a vortex such as the 
vital motion. 
Solids, it is plain, are necessary to these bodies, for the 
maintenance of their forms; and fluids for the conservation of — 
motion in them. ‘Their tissue, accordingly, is composed of 
network and plates, or of fibres and solid lamine, within whose 
interstices are contained the fluids; it is in these fluids that 
the motion is most continued and extended. Foreign sub- 
stances penetrate the body and unite with them; they nourish 
the solids by the interposition of their sialniulole and also de- 
tach from them those that are superfluous. It is in a liquid 
or gaseous form that the matters to be exhaled traverse the 
pores of the living body ; but in return, it is the solids which 
contain the fluids, and by their contraction communicate to 
them part of their motion. 
This mutual action of the fluids and solids, this tmhsidon of 
molecules, required considerable affinity in their chemical — 
composition ; and such is the fact—the solids of organized bo- 
dies being mostly composed of elements easily convertible an 
fluids or gases. 
The motion of the fluids needing also a constantly repeated 
action on the part of the solids, and communicating one to 
them, required in the latter both flexibility and ciiptebiligey 
and accordingly we find this character nearly general in alk 
organized solids.. : 
This structure, common to all living baleen; this ar éolar tis- 
sue, whose more or less flexible fibres or lamin intercept fluids 
more or less abundant; constitutes what is called the organi~ 
zation. As a consequence of what we have said, it follows, _ 
that life can be enjoyed by organized bodies only. 
Organization, then, results from a great variety of arrange. 
ments, which are all conditions of life; and it is easy to con- 
ceive, that if its effect be to alter either of these conditions, so 
y, 
a 
