XXX 



THEODOR SCHWANN 



1810-1882 



Theodor Schzvann, the son of a Prussian printer, was horn at 

 Neuss, Prussia, December y, 1810. He first studied medicine, hut 

 ivas persuaded to devote himself to science hy Johannes Mueller, 

 who appointed him assistant in the anatomical museum. In 18^8 he 

 was called to the Catholic University of Louvain, and later removed 

 to Liege. One of the first to suggest the chemical explanation of 

 life, he discovered the presence and function of pepsin as a ferment 

 in digestion. In J8jp he established his great theory that all life is 

 composed of inter-connected cellular units — a conception which ^^ 

 revolutionized biology. He died at Liege on January 11, 1882. (-ru?^ 



CELL THEORY * 



The various opinions entertained with respect to the fundamental 

 powers of an organized body may be reduced to two, which are essen- 

 tially 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 neces- 

 sary 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 es- 

 sentially different from all the powers of inorganic nature, because 

 action goes on in the latter quite blindly. A certain impression is 

 followed of necessity by a certain change of quality and quantity, 



* Translated from MikroskopiscJie Untersuchungcn iiber die Wachstum der 

 Tiere und der Pflanccn (Berlin, 1839) by Henry Smith in the Publications of 

 the Sydenham Society (1847). 



245 



