THE CELL 21 



Tissue Culture. One of the aehieveiueuts of modem research has 

 been the deveIo})meiit of methods whereby small fragments of tissues 

 com])osed of various cells can be isolated and grown a])art from the 

 organism in especially prepared media. If proper conditions of 

 warmth, aeration, and asepsis are maintained in the culture media, 

 the cells of such tissue cultures may be kei)t alive, grow, and divide 

 mitotically over a considerable period and a number of generations. 

 It has been ])ossible by these methods to isolate certain cell types, 

 observe their growth, and determine whether they maintain certain 

 characteristics or transform to other types. It also opens a method 

 of attack upon the jihysical and chemical properties of the various 

 cells maintained under culture conditions. One of the outstanding 

 contril)utions has been the study of growth and regeneration of 

 nerve cells. Still other observers have studied the behavior of other 

 ty])es of cells under diflPerent physical and chemical experimental 

 conditions. 



Another method of attacking the study of living cells utilizes a 

 micromanipulating ap])aratus in conjunction with the microscope. 

 By means of this apparatus those proficient in the technique have 

 been able to dissect cells or inject minute quantities of chemicals into 

 them. As a result of these microdissections and microchemical 

 studies much has been learned about the physical and chemical 

 nature of living cells. 



REFERENCES. 



Bensley, R. R., and Gersch, I. 193.3. Studies on cell structure by the 



freezing-drying; method, Anat. Rec, 57, 369. 

 Bensley, R. R., and Hoerr, N. L. 1934. Studies on cell structure by the 



freezing-drying method: V. The chemical basis of the organization of the 



cell, Anat. Rec, 60, 251. 

 Studies on cell structure by the freezing-drying method: VI. The 



preparation and properties of mitochondria, Anat. Rec, 60, 449. 

 Cameron, Gladys. 1935. Essentials of Tissue Culture Technique. Farrar 



and Rinehart, Inc., New York. 

 Chambers, R. 1927. Microdissection studies: The visible structure of cell 



protoplasm and death changes, Am. .Jour. Physiol., vol. 43. 

 Cowdry, E. V. 1924. General Cytology, Chicago, 111., Univ. Chicago Press. 

 Gray, J. 1931. E.xperimental Cytology, Cambridge, Cambridge Univ. Press. 

 HoBER, R. 1930. The present conception of the structure of the plasma 



membrane, Biol. Bull., 58, 1-17. 

 Lewls, F. T. 1925. A further study of the polyhedral shapes of cells, Parts I, 



II, III, Proc Am. Acad. Arts and Sci., Boston, 61, 1. 

 1928. The effect of cell division on the shajje and size of he.xag- 



onal cells, Anat. Rec, vol. 33. 

 Schrader, F. 1934. On the reality of spindle fibers, Biol. Bull., 67, 519. 

 Wilson, E. B. 1928. The Cell. New York, The Macmillan Company. 



See Appendix for general text references. 



