186 THEORY OF THE CELLS. 
THEORY OF THE CELLS. 
The whole of the foregoing investigation has been con- 
ducted with the object of exhibiting from observation alone the 
mode in which the elementary parts of organized bodies are 
formed. Theoretical views have been either entirely excluded, 
or where they were required (as in the foregoing retrospect of 
the cell-life), for the purpose of rendering facts more clear, or 
preventing subsequent repetitions, they have been so presented 
that it can be easily seen how much is observation and how 
much argument. But a question inevitably arises as to the 
basis of all these phenomena; and an attempt to solve it will 
be more readily permitted us, sce by making a marked sepa- 
ration between theory and observation the hypothetical may be 
clearly distinguished from that which is positive. An hypo- 
thesis is never prejudicial so long as we are conscious of the 
degree of reliance which may be placed upon it, and of the 
grounds on which it rests. Indeed it is advantageous, if not 
necessary for science, that when a certain series of phenomena 
is proved by observation, some provisional explanation should be 
conceived that will suit them as nearly as possible, even though 
it be in danger of being overthrown by subsequent observations; 
for it is only in this manner that we are rationally led to new 
discoveries, which either establish or refute the explanation. It 
is from this point of view I would beg that the following theory 
of organization may be regarded ; for the inquiry into the source 
of development of the elementary parts of organisms is, in fact, 
identical with the theory of organized bodies. 
The various opinions entertained with respect to the funda- 
mental powers of an organized body may be reduced to two, 
which are essentially different from one another. The first is, 
that every organism originates with an inherent power, which 
models it into conformity with a predominant idea, arranging 
the molecules in the relation necessary for accomplishing certain 
purposes held forth by this idea. Here, therefore, that which 
arranges and combines the molecules is a power acting with a 
definite purpose. A power of this kind would be essentially 
different from all the powers of inorganic nature, because action 
