[UKIVERSIT7] 



CHAPTER I. 



THE GENERAL CHARACTERS OF CELLS. 

 BY S. STRICKER. 



INDEPENDENCE OF CELLS. In the year 1835, Joh. Miiller 

 commenced an essay on Organism and Life* with the following 

 words of Kant : " The cause of the particular mode of existence 

 of each part of a living body resides in the whole, while in 

 dead masses each part contains this cause within itself." 



From this quotation it is sufficiently evident what role was 

 at that time ascribed to the microscopic constituents of the 

 body from the point of view taken by biologists. Fibres, cells, 

 spheroids, and granules were distinguished under the micro- 

 scope, and it was stated that these structures were not inde- 

 pendent so far as their growth was concerned, but were subject 

 to the influence of the vessels. They were on this account 

 differentiated from vegetable tissues, which were supposed to 

 possess an independent existence. A few experiments, how- 

 ever, led to the establishment of certain analogies between 

 vegetable and animal cells. Joh. Miiller himself, for example, 

 pointed out the analogy that obtains between the cells of the 

 chorda dorsalis and vegetable cells ; and subsequently, when 

 Valentin discovered the nuclei of the cells of the epidermis, he 

 commented upon their similarity to those of the cells of plants. 



Henlef made a decided step in advance when he proved that 



* Physiologie, Band i., 1835. 



f Symb. ad. Anat. vill. intest. Berlin, 1837. 



