PEOTOPLASM, THE SEAT OF LIFE. 33 1 



separated itself from the surrounding cell-substance (proto- 

 plasma). As we have already pointed out, the cells, with 

 their simple attributes, are so many citizens, who by 

 co-operation and differentiation build up the body of even 

 the most perfect organism ; this being, as it were, a cell 

 republic (p. 301). The fully developed form and the vital 

 phenomena of such an organism are determined solely by the 

 activities of these small albuminous corpuscles. 



It may be considered as one of the greatest triumphs o: 

 recent biology, especially of the theory of tissues, that we 

 are now able to trace the wonder of the phenomena of life 

 to these substances, and that we can demonstrate the 

 infinitely manifold and complicated physical and chemical 

 properties of the albuminous bodies to he the real cause of 

 organic or vital phenomena. All the different forms of 

 organisms are simply and directly the result of the combi- 

 nation of the different forms of cells. The infinitely 

 manifold varieties of form, size, and combination of the cells 

 have arisen only gradually by the division of labour, and by 

 the gradual adaptation of the simple homogeneous lumps of 

 plasma, which originally were the only constituents of the 

 cell-mass. From this it follows of necessity that the 

 fundamental phenomena of life — nutrition and generation — 

 in their highest manifestations, as well as in their simplest 

 expressions, must also be traced to the material nature of 

 that albuminous formative substance. The other vital 

 activities are gradually evolved from these two. Thus, 

 then, the general explanation of life is now no more 

 difficult to us than the explanation of the physical properties 

 of inorganic bodies. All vital phenomena and formative 

 processes of organisms are as directly dependent upon the 



