276 Colchicine 



Some of the complexities have aheady been scrutinized in the first 

 chapters of this book. A few more considerations about this particular 

 problem of multiplying the numbers of mitoses by destroying their 

 spindle will be useful for future workers in this field. While the 

 number of papers published about the colchicine method appears 

 to be on the decrease, so far as can be assessed, for colchicine is not 

 always mentioned in the titles, much work remains to be done. This 

 chapter will point out several unexplored fields. 



9.2: Theoretical Considerations 



Most of the American authors, following the first papers of Allen, 

 those of Brues^^- -**•-!• -- on liver regeneration, and the tissue culture 

 work of Bucher--^ and Ludford,*''- considered colchicine simply as a 

 means of stojjping any mitosis at metaphase. The complexities of 

 colchicine pharmacology (Chapter 7) should alone call for more cau- 

 tion. 



A. P. Dustin, Sr., in a paper published in 1936, but which could 

 not have received much publicity, demonstrated the utility of colchi- 

 cine as a tool.^i He had noticed the increased number of divisions in 

 the wall of a parasitic cyst in a mouse, a fact which was the starting 

 point for experiments rjn the healing of ^vounds, revie^ved further on 

 in this chapter. In his own words, "colchicine enables the detection 

 of the otherwise invisible state of preparedness to mitosis." * It 

 throws into an abortive division all the cells which are ready to 

 divide, or had been prepared for mitosis, for instance, under the in- 

 fluence of endocrine or other stimidi. This was in agreement with 

 the line of thought which had led to the discovery of colchicine's 

 action in 1934, and which was the study of the regulation of mitotic 

 growth. 



The theories of "mitotic arrest" or "arrest after mitotic stimula- 

 tion" are conflicting. In work where tlie location of mitoses is the 

 main purpose and where no quantitative data are required, colchi- 

 cine is useful whatever the opinion one has about a possible stimula- 

 tion of mitosis. This problem, however, should not be overlooked. 

 For instance, several authors have thought it possible to calculate 

 from the number of mitoses found after colchicine, the average dina- 

 tion of these mitoses, had they not been arrested. This dmation is, 

 of course, an indication of the rapidity of cellular growth in the 

 tissues studied. It should be clearly realized that such calculations 

 imply several unknown factors, and they have a precise signification 

 only if the following conditions are fulfilled: 

 1. Colchicine arrests all mitoses, shortly after it has been injected 



and until the end of the experimental period. 



* A. P. Dustin, "La Colchicine, Reactif de llniniinence Caryocinetique," Arch. 

 Portugaises Sci. Biol., 5(1936), p. 41. 



