20 SUBCELLULAR PARTICLES 



a concept which, like 'the average man' or 'the beautiful woman,' is useful hut 

 somewhat unreal. Yet some may not realize the degree of quantitative hetero- 

 geneity, even among homogeneous cells like the parenchymatous cells of liver. 

 Figure 20 is intended to emphasize that every cytological entity and chemical or 

 enzyme studied by //; .*■//// methods exhibits such t]uantitative differences between 

 the centrolobular and peripheral cells of the hepatic lobule." It is possible that 

 these dififerences are related to factors like the quality of blood flowing to the 

 cells (31). 



We await with interest the study of these cells in Dr. Oliver Lowry's labora- 

 tory. Still another method of biochemical cytology, micro-techniques applied to 

 tissue sections, is being employed, in this case to dissected areas of frozen sec- 

 tions. These direct chemical analyses of centrolobular cells and peripheral cells 

 will provide opportunity for evaluating the staming observations. 



CONCLUSION 



The developments in biochemical cytology show that what seemed simple has 

 become complex, what appeared separate is interrelated, what looked homogeneous 

 is now heterogeneous. Our knowledge of the cell moves towards heterogeneity, 

 but our approach to its study moves towards homogeneity. It would be over- 

 statement to consider that the various approaches of biochemical cytology are 

 the same and that it is therefore difficult, at symposia like these, to distinguish a 

 biochemist from a microscopist. Yet the movement is there — towards removal 

 of barriers, towards a common language, towards common approaches and 

 common concepts. 



1 am intlcbtwl to iny colleagues. Dr. Edward Essncr, for the electron micrographs in figures 3, 

 4, 6, II and 12; Dr. Herman W. Spater fur figure ij; Miss Bertha Masek for assistance in 

 preparing the slides from which figures 14, 15, 16, iS antl 19 were photographed; Mr. L. ). 

 Walker for the photography, including photomicrography: and Mr. Stanley Waine for the art 

 work in figures 8, 9, 17 anil 20. 



REFERENCES 



Abercrombie, M. and R. D. Harkness. Proc. Roy Soc. Loudon, ser. B 138: 544, 1951. 

 Allfrey, V. G. AND I. A. MiRSKY. This volume, p. 186. 



3. Brachet, J. Biochemical Cytology. New York: Acad. Press, 1957. 



4. Birbeck, M. S. C, and E. H. Mercer. Nature 178: 985, 1957. 



5. Chance, B. In: Enzymes, Units of Biological Stnictinc and Function . edited by O. H. 

 Gaebler. New York: Acad. Press, 1956, p. 447. 



6. Chevremont, M. Notions de Cytologic et Histologic. Liege: Editions Desoer, 1956. 



7. Daoust, R. /. Nat. Cancer Inst. 15: 1447. 1955. 



^ The evidence for this diagram comes from the work of many laboratories, including our 

 own. It was first presented at a meeting of the New York Pathological Society (31), and will 

 be describeil in ilctail elsewhere. 



