Experimental Growth in Animals 215 



jected with "theelin" alone showed 20 to 30 dividing cells. After 

 colchicine, this was increased to more than 1500 in about 10 hours. 

 In one experiment in which "theelin" and colchicine were injected 

 simultaneously, the authors wrote that "the general impression is 

 that approximately every other cell is in mitosis."* I'hese results 

 aroused great interest, and marked one of the starting points for 



Fig. 9.1 — Graphical representation of the course of cell division in a fibroblast culture 

 treated by colchicine (1/20,000,000). During the two first hours, no notable changes. 

 Later, progressive accumulation of arrested mitoses. Each horizontal line represents 

 one mitosis; it is interrupted at the end of metaphase. Any vertical line indicates th- 

 number of visible mitoses at one moment, that is to say, the mitoses which should b 

 seen in a fixed preparation. This number progressively increases under the influenc 

 of colchicine. The rate of apparition of new prophases is not disturbed with this con- 

 centration. There is no mitotic stimulation. (From a cine-micrographic recording. After 

 Bucher, 1939) 



e 



le 

 ce 



colchicine research outside of the Brussels laboratory. Together with 

 the discovery of colchicine polyjjloidy in 1937, this study initiated 

 the publication of a great number of papers in which colchicine was 

 mainly considered as a tool for making mitotic growth more visible 

 and easier to analyze. 



However, any tool has its advantages and its shortcomings. Many 

 workers do not appear to have considered carefully the fundamental 

 problems involved in what Allen called the "freezing" of mitoses. 



* Ihld.. p. 325. 



