84 



LIFE: ITS NATURE AND ORIGIN 



ing upon tissue culture methods originated in the laboratory of 

 Professor Ross G. Harrison of Yale University. Dr. Alexis Carrel 

 (Nobel prize, 1912) and his collaborators at the Rockefeller Insti- 

 tute for Medical Research were able to keep alive a culture of 

 chicken heart cells in an embryonic juice medium for over a 

 third of a century. Professor Robert Chambers of New York 

 University made moving-picture films of a group of heart-muscle 

 cells beating rhythmically in tissue culture, while from the other 

 side of the culture chamber rapidly growing cancer cells invaded 



Figure 8. Electron micrograph of tobacco mosaic virus (x 18,000). (Courtesy 



University of Toronto) 



the "heart" and interfered with its contraction as a unit (fibrilla- 

 tion). 



Where large numbers of cells are associated in community life, 

 as in multicellular plants and animals, most of the cells become 

 so highly specialized or differentiated (as in tissues, organs, or 

 blood), that they are quite incapable of carrying on an inde- 

 pendent existence. Therefore, if one organ or even a small group 

 of cells fails, the whole organism may perish. The deadly prus- 

 sic or hydrocyanic acid produces speedy death by inactivating 

 certain cells in the medulla which control respiration and heart- 

 beat. It is not generally recognized that sulfuretted hydrogen has 

 an action similar to that of prussic acid; but in some respects it 

 is even more dangerous because its fixation is irreversible. The 



