224 Colchicine 



and their growth could be studied for as long as 36 hours. The 

 number of mitoses was considerably increased by colchicine, and 

 the authors have indicated that this "stathmokinetic index," as it has 

 been called, may throw considerable light on many problems of 

 normal and neoplastic celhdar division. Some of these will be men- 

 tioned in Chapter 10. 



Very small amounts of colchicine are effective; dilutions of 

 1:1,000,000 were used. The alkaloid may disturb slightly the normal 

 maturation of cells of the erythroblastic series. This is only visible 

 after 12 hoius hi vitro, and for most experiments, important data can 

 be recorded from 4 to 8 hours after colchicine. The action of em- 

 bryonic extracts" and that of irradiation with X-rays^ have been 

 studied on normal marrow. This has also been compared with 

 marrow from patients suffering from Addison-Biermer anemia (cf. 

 Chapter 8) , polycythemia and leukemia (Chapter 10) , and thalas- 

 semia (Cooley's anemia) ." 



Figure 9.5 demonstrates that the mitotic activity of erythroblasts 

 (young red blood cells) is depressed by absence of oxygen. This ex- 

 periment was carried on in a vessel in which a partial vaciuuu could 

 be maintained. It is made clear by colchicine that the younger cells, 

 the basophil erythroblasts, are more depressed than the more 

 differentiated ones, which have already some hemoglobin. These 

 important results are to be compared to those mentioned above, on 

 the importance of oxygen for mitosis in the epithelial cells of the 

 mouse's ear.-" This might have passed entirely imnoticed if a tool 

 had not existed to increase the number of visible mitoses and make 

 counting a simple proposition. It must, however, always be kept in 

 mind that control experiments shotdd be made, for it remains to be 

 proved that colchicine, which has such a wide variety of pharma- 

 cological effects (Chapter 7) , does not disturb some mitoses more 

 than others. These experiments are, of comse, entirely based on 

 the assumption that the alkaloid does no more than "frce/e" the 

 mitoses at metaphase.-' -^' ^^ 



9,4: Hormone-stimulated Growth 



A considerable number of papers have been published following 

 the contributions of Allen, Smith, and Gardner.^ It is not con- 

 templated to review them all here, even if such a task were possible, 

 for many papers of endocrinological interest do not mention in their 

 titles that colchicine has been used, and it has become impossible to 

 keep up a complete set of references. Table 9.4 gives a summary of 

 some of the work which has been jHiblished. It is evident that the 

 sex hormones have been the most studied, partly because their iso- 

 lation and chemical identification took place in the period im- 



