I 3 4 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 



