No. 589] THE EVOLUTION OF THE CELL 



7 



mation. Unfortunately this is so far from being the case 

 that it is practically impossible, in this country at least, 

 to find any one amongst the educated classes to whom the 

 words "cell" and "cytology" convey any meaning at all, 

 except amongst those who have interested themselves 

 specially in some branch of biology. Consequently, any 

 discussion concerning the eel], although it may deal with 

 the most elementary processes of life and the fundamental 

 activities and peculiarities of living beings, ranks in popu- 

 lar estimation as dealing with some abstruse and recon- 

 dite subject quite remote from ordinary life and of inter- 

 est only to biological specialists. It must, however, be 

 pointed out that the general state of ignorance concern- 

 ing these matters is doubtless in great part due to the fact 

 that an objective acquaintance with cells can not be ob- 

 tained without the use of expensive and delicate optical 

 instruments. 



I propose in this address to deal with an aspect of cytol- 

 ogy which appears to me not to have received as yet the 

 attention which it deserves, namely, the evolution of the 

 cell itself and of its complex organization as revealed by 

 the investigation of cytologists. Up to the present time 

 the labors of professed cytologists have been directed 

 almost entirely towards the study of the cell in its most 

 perfect form as it occurs in the Metazoa and the higher 

 plants. Many cytologists appear indeed to regard the 

 cell, as they know it in the Metazoa and Metaphyta, as 

 the beginning of all things, the primordial unit in the 

 evolution of living beings. 4 For my part I would as soon 

 postulate the special creation of man as believe that the 

 Metazoan cell, with its elaborate organization and its ex- 

 traordinarily perfected method of nuclear division by 

 karyokinesis, represents the starting-point of the evolution 



* For example, my friend Dr. C. E. Walker, in an article in Science Prog- 

 ress (Vol. VII, p. 639), after stating that "The unit of living matter, so 

 far as we know, is the cell," proceeds to deal with "that form in which it is 

 found in the multicellular and the majority of unicellular organisms, both 

 animal and vegetable" and then describes the typical cell of the cytologist, 

 with nucleus, cytoplasm, centrosome, chrondriosomes, and reproduction with 



