of the cell, are described. A few of those which have helped greatly in 

 establishing the concept of the cell that we currently possess should be 

 mentioned. In the first place, ability to fix and section biological material 

 in such a way as to make it suitable for electronmicrographic studies has 

 reached the level at which it is possible to study structures at the ang- 

 strom level with about the same degree of confidence that we can accord 

 the light microscope at the micron level. In the second place, modern 

 methods of tissue homogenization and differential centrifugation have 

 made it possible to separate cellular components in sufficient amount and 

 with sufficient purity to allow determination of physical and chemical 

 potentialities. Finally, radioactive tracers and more or less specific colori- 

 metric methods may be used to provide data on both the degree and site 

 of synthesis of many important products of cellular metabolism. A com- 

 bination of all three general methods of attack may go far, as it has for 

 instance in the case of mitochondria, in determining the relationship 

 between structure and function. 



If the road ahead seems long and tortuous, we may derive consolation 

 from the fact that we have traveled far since Schleiden and Schwann and 

 much of this journey has been made in the past few decades. The sincere 

 student will always recognize his debt to the past and will also realize 

 that the "new fact" is often nothing more than confirmation of an old 

 suspicion. Ideas are not accepted without travail. The late Prof. C. L. 

 Huskins commented that there are commonly three stages: '"(l) we 

 don't believe it; (2) it's of little or no significance; (3) we knew it long 

 ago." This process merely indicates a natural tendency to backdate 

 knowledge once a suspicion is confirmed. The seeds of progress have 

 often been planted in the past, frequently unconsciously, and history 

 should be read not only for pleasure but for profit. History is a mine 

 of ideas not a worked-out vein. 



BIBLIOGRAPHY 



Bensley, R. R. and Hoerr, N. L., 1934. "Studies on Cell Structure by the 

 Freezing-Drying Method. VI. The Preparation and Properties of Mito- 

 chondria," Anat. Record, 60, 449-455. 



Fox, S. W., 1960. "How Did Life Begin?", Science, 132, 200-208. 



Hughes, A., 1952. "Some Historical Features in Cell Biology," Intern. Rev. 

 CytoL, 1, 1-7. 



Hughes, A., 1959. "A History of Cytology," Abelard-Schumann, London. 



Huskins, C. L., 1951. "Science, Cytology and Society," in "Symposium 

 on Cytology," Michigan State University Press, E. Lansing, Mich., pp. 

 53-69. 



Kingsbury, B. F., 1912. "Cytoplasmic Fixation," Anat. Record, 66, 39-52. 



6 / CHAPTER 1 



