THE CELL DOCTRINE. 59 



Thus did physiologists adhere to the original free 

 cell formation of Schleiden and Schwann. Singu- 

 larly, Dr. Carpenter,* who expressly states, in his 

 Manual of Physiology, edition of 1865, that he has 

 been led to the view of Professor Beale by com- 

 parison of the results of the recent inquiries of sev- 

 eral British and Continental histologists with those 

 of his own studies, says, a few pages further on (p. 

 150), "New cells may originate in one of two prin- 

 cipal modes; either directly from a previously exist- 

 ing cell, or by an entirely new process in the midst 

 of an orgauizable blastema." He then proceeds to 

 give the two methods in detail, without in any way 

 denying the latter. 



VIRCHOW, 1858. 



Less than two years later, August 20th, 1858, Prof. 

 Virchow published his " Cellular Pathology as based 

 upon Physiological and Pathological Histology." 

 According to him, the cell is the only possible start- 

 ing-point for all biological doctrines. This cell can 

 only originate from a previously existing cell, taking 

 its primary origin from the ovum, and the Harveian 

 maxim omne vivum ex ovo, becomes in its special 

 application, omnis cellula e celluld. This is true of all 

 physiological and pathological processes in the vege- 

 table and animal. In all editions of " Cellular 

 Pathology" which we have met, the typical cell is 

 described as consisting essentially of "cell wall," 



* Carpenter, Manual of Physiology, London : 1865. Note on 

 p. 14. 



