^^^ tui 



THE MITOCHONDRIAL CONSTITUENTS OF PROTOPLASM. 143 



tion and sometimes it is not. Such a formation would develop great siu"face ten- 

 sion. Butschli is to be credited for the first attempt to explain the phenomena of 

 mitosis in terms of physics and chemistry. Apparently he was right in explaining 

 certain kinds of amoeboid motion on the basis of surface tension, though he beUeved 

 that the motion took place through the local enlargement of the alveoli. In spite 

 of many criticisms this theory is quite stimulating and helpful in the study of cell 

 physiology. 



These theories are not so clear-cut as they appear to be. Many amendments 

 and subsidiary hypotheses with all grades of meaning have been introduced which 

 we have not time here to consider. The attempts to generalize have not been 

 fruitful. We constantly meet with filamentous, granular, and net-like appearances 

 in protoplasm, but they are transitory and superficial. The theories go so far 

 and no further. In my opinion they do not even touch on the main point at issue. 

 They do not in any way help us to understand the nature of vital processes or the 

 special phenomena of polarity and bilaterahty in the cell, and the reason is not far 

 to seek. It is because cytologists are usually versed in the use of the microscope 

 and fail to realize that in protoplasm the most important things are the things 

 unseen. Accordingly^, attention has been paid to only the visible constituents 

 and the rest have been ignored. It must be admitted that cytologists as a whole, 

 with present-day equipment and training, are not fitted as the biochemists are 

 for the study of the most fundamental of problems, the nature of hfe. 



Vital phenomena are totally incomprehensible unless there exists some struc- 

 tural organization in protoplasm. Cellular polarity and bilaterahty must depend 

 on it. Cells are the unit structures in our bodies, but each and every one of them 

 a complicated and highly organized unit. Each is a httle factory which quickly 

 rings about chemical changes, possible only in rare instances outside of the body, 

 slowly with the aid of considerable temperature and pressure and much compli- 

 catedfcnachinery. That the cytoplasm is organized locally just as the great fac- 

 tory is organized in space is evident from the fact that when it is thoroughly mixed 

 life is no longer possible. It has been proved over and over again that this 

 organization does not reside in the visible constituents of the protoplasm, because 

 their distribution can easily be altered without modifying either the polarity or 

 the bilaterahty, as the case may be, or disturbing to any great extent the vital 

 processes going on. Mitochondria, pigment, and secretion granulations, fat, hpoid, 

 and all the other formed bodies are relatively unimportant. It is to the optically 

 homogeneous ground-substance that we must look, and our microscopes will help 

 us not at all. We must extend our conceptions to include a morphology of the 

 ultramicroscopic and invisible; otherwise we fail. 



The intensive study of the mitochondrial constituents of protoplasm has 

 brought us an important point of contact with recent advances in chemistry. In 

 cytology as in physiology the mechanistic philosophy is the only fruitful one. 

 The old giant molecule or biophore hypothesis of Ehrlich is being rapidly discarded 

 and we are beginning to entertain the entirely opposite view that vital phenomena 

 are due to the orderly interaction of relatively simple substances, often of inorganic 



