14 



FIRST LECTURE. 



Schwann, the founder of modern histology, taught : " What 

 the crystal is in regard to the inorganic, so is the cell in the 

 sphere of life." As the former shoots forth from the mother- 

 lye, so also, in a suitable animal fluid, are developed the 

 constituents of the cell, nucleolus, nucleus, covering, and 

 cell contents. 



This view was embraced during many years. It explained 

 everything so conveniently ! 



This was, however, over-hasty. Two highly endowed in- 

 vestigators, Remak and Virchow, exposed the error ; the 

 former for the embryonic, the latter for the diseased human 

 body. 



The organic kingdom forms a continuity from the Bathybius 

 to man. We do not hesitate an instant to acknowledge that 

 this is also our conviction. 



There is an old well-known saying : " Omne vivum ex 

 ovo," and in imitation of this sentence : " Omnis cellula e 

 cellula." The cell arises from the cell ; a spontaneous origin, 

 in the sense of Schivaun, does not occur. 



We know but one certain method of increase of the cells 

 of our body. 



The protamceba, Haeckel's non-nuclear cytode (Fig. 2), 

 divides itself into two beings by constriction. Each portion 



grows, by a predominant reception of 

 material, to a new protamoeba. This is 

 also the method of propagation of the 

 nucleated cell of the human body. 

 Nucleus and protoplasm divide ; from 

 one structure are formed two, and so 

 forth. Our figure (Fig. 18) shows this 

 multiplying process of embryonic blood 

 corpuscles. When, however, the cell 

 has once become surrounded by an 

 a young deer embryo fat a, the envelope or a capsule, when the proto- 



most globular cells ; b to J, their 1 l l 



process of division. plasma is imprisoned, then (Fig. 19) the 



contrast of the active and the passive is strikingly presented. 

 The capsule remains stiff and quiet, the cell in prison 



Fig. 18. -Klood corpuscles of 



