THE CELL DOCTRINE. 115 



out distortion of its own principle or disregard of 

 actual facts, of consistent application to a larger num- 

 ber of processes of tissue-building in health and dis- 

 ease, than any other theory proposed. 



In conclusion, then, it may be stated, 1st, that 

 the " cell," or " elementary part," originating only 

 in a pre-existing cell, is the ultimate morphological 

 element of the tissue of animals and plants. 



2d. That the cell, contrary to the belief of the 

 earlier histologists, and, indeed, many later observ- 

 ers, is rarely vesicular in its structure, but generally 

 more or less solid throughout. 



3d. That the cell is composed of "germinal" or 

 living matter which is central, and includes " nu- 

 cleus," "endoplast," "protoplasm" and "sarcode;" 

 and of "non-germinal," or "formed" matter, which 

 is peripheral, and corresponds with "cell wall" and 

 " intercellular substance." 



4th. That this germinal matter of the cell in a 

 part or all of its substance, may assume a special 

 morphological state, usually round or oval, com- 

 monly known as the " nucleus" of the cell, which, 

 when present, is always a young centre of germinal 

 matter; but that in other instances both animal and 

 vegetable cells may be complete without this special 

 form of germinal matter or " nucleus," as in the non- 

 nucleated amoabae and protogenes primordialis of 

 Hseckel, the non-nucleated monads of Cienkowsky, 

 and in the leaf of Sphagnum, in such Algse as Hy- 

 drodictyon, Vaucheria, and Caulerpa, and in young 

 germinating ferns. 



5th. That in consequence of these facts, it cannot 



