134 CELL THEORIES. 
But the mere tissue-life in individual corpuscles 
will not account for the phenomena of development 
without the addition of a larger life or a formative 
principle common to the whole individual, and it 
would be of incalculable advantage in the just con- 
ception of pathological phenomena, if the central 
and tissue lives were more generally distinguished 
than they are. [No one has yet reduced, in a satis- 
factory way, any of the properties above mentioned 
as belonging to corpuscles, namely, irritability, con- 
tractility, nutrition and reproduction, to the laws of 
unorganized matter; and having regard to that 
circumstance, and to the complicated phenomena of 
development of higher organisms, exhibiting series 
of changes unlike anything in the organic world, it 
is legitimate to conclude that in living beings there 
is a superadded element acting on the textural 
units individually, and that such an element con- 
trols likewise the development of the organism. 
The neoplasms of the pathologist afford abundant 
example of corpuscular life breaking loose from 
the central control by means of which it is utilized 
in health for the construction and continuance of 
definite organs.] 
Still proceeding on the principle of life within 
life, we may go further and assert that a larger life, 
or series of developmental changes from a simple 
