THE PROrOPLASMIC SYSTEM 



from the fixed. Processes too fleeting to be followed 

 exactly in the living can be followed in their single steps in 

 the fixed. By thus supplementing the study of the living 

 by that of the fixed ground-substance, we may approach 

 the understanding of the basic structure of cytoplasm. My 

 confidence in the value of the study of properly fixed cells 

 rests upon the fact that such study has confirmed my 

 observations of the extremely delicate momentary changes 

 in the ectoplasm of living cells. Without ever discounting 

 the postulate that the living cell is the basis, control and 

 aim of biological investigation, I have come to appreciate 

 the value of proper fixation. But since the use of fixation 

 has been and is questioned by many workers, I must for a 

 moment dilate on this point. 



When at the end of the last century Fischer^ and Hardy^ 

 independently inveighed against fixation of protoplasm, 

 neither made much impression. But the impression grew; 

 to-day we discern a reaction of no mean proportion against 

 the study of fixed cells. Some histologists adopt an 

 apologetic air, offering their findings on fixed tissues in all 

 but a furtive manner; others have given themselves over 

 to the cinematograph or to the culture of living tissue 

 removed from the animal. 



Now without doubt conclusions as to living protoplasmic 

 structure drawn from study of dead cells should ever be 

 subjected to severest criticism. He who works with dead 

 cells should never be under delusions that he has to do with 

 other than a dead thing. I do not believe that any com- 

 petent histologist takes any other view. And yet, there 

 is often inference by those who hold lightly all work on 

 fixed cells, whatever its purpose or conclusions, that the 

 investigator of fixed, sectioned and stained cells forgets 



1 Fischer, l8g(). 

 - Hardy, iSgg. 



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