22 



THE AMERICAN NATURALIST 



[Vol. L 



an organism of very considerable complexity of structure 

 and multiplicity of parts. The truth of this proposition 

 is sufficiently obvious even from simple inspection of the 

 structural details revealed by the microscope in cells in 

 the so-called "resting condition," but still more so from 

 a study of their activities and functions. The vital proc- 

 esses exhibited by the cell indicate a complexity of or- 

 ganization and a minuteness in the details of its mechan- 

 ism which transcend our comprehension and baffle the 

 human imagination, to the same extent as do the immen- 

 sities of the stellar universe. If such language seems 

 hyperbolic, it is but necessary to reflect on some of the 

 established discoveries of cytology, such as the extraor- 

 dinary degree of complication attained in the process of 

 division of the nucleus by karyokinesis, or the bewildering 

 series of events that take place in the nuclei of germ-cells 

 in the processes of maturation and fertilization. Such 

 examples of cell-activity give us, as it were, a glimpse 

 into the workshop of life and teach us that the subtlety 

 and intricacy of the cell-microcosm can scarcely be exag- 

 gerated. 



On the assumption that an organism so complex and 

 potent was not created suddenly, perfect and complete 

 as it stands, but arose, like all other organisms, by pro- 

 gressive evolution and elaboration of some simpler form 

 and type of structure, it is legitimate to inquire which of 

 the various parts of the cell are the older and more prim- 

 itive and which are more recent acquisitions in the course 

 of evolution. But it must be clearly pointed out, to start 

 with, that the problem posed in such an inquiry is per- 

 fectly distinct from, and independent of, another point 

 which has often been discussed at length, namely, the 

 question whether any parts of the cell, and if so which 

 parts, are to be regarded as "living" or "active" in dis- 

 tinction to other parts which are to be regarded as "not- 

 living" or "passive." This discussion, in my opinion, 

 is a perfectly futile one, of which I intend to steer clear. 



We may agree that in any given cell or living organism, 



