THE CELL AND PROTOPLASM. 



103 



significant fact that protoplasm is to be regarded 

 as a substance not only of chemical but also of 

 high mechani- 

 cal complex- 



as a simple ~, 

 homogeneous 

 compound or <L. 

 as a mixture 

 of such com- 

 pounds is ab- 

 solutely falla- . 

 cious. Proto- 

 plasm is to-day 

 known to be 

 made up of 

 parts harmoni- 

 ously adapted 



in such a way 

 as to form an 

 extraordinarily intricate machine ; and the micro- 

 scopist of to-day recognizes clearly that the acti- 

 vities of this material must be regarded as the 

 result of the machinery which makes up proto- 

 plasm rather than as the simple result of its 

 chemical composition. Protoplasm is a machine 

 and not a chemical compound. 



STRUCTURE OF PROTOPLASM. 



The structure of protoplasm is not yet 

 thoroughly understood by scientists, but a few 

 general facts are known beyond question. It is 



_ A cell ag . t appeara to the modern micro . 



scope, a, protoplasmic reticulum; 6, liquid 

 in its meshes; c, nuclear membrane; d, 

 nuclear reticulum ; e, chromatin reticulum ; 

 /, nucleolus-.^centrosome; A.centrosphere; 

 ', vacuole ; j. inert bodies. 



