786 Colchicine 



hours: O 



10 



15 



20 



25 



Fig. 7.6 — Modifications of the leukocyte count in the blooci of a rabbit injected 7.8 

 mg'kg colchicine, after 5.2 mg kg atropine sulfate. (After Dixon and Maiden'') 



marrow relati\cl\ dcnuticd ol corpuscles."* 1 his is no true stimu- 

 lation, and the authors are more precise when in the same j^aper 

 they mention that the cells "are swept out . . . oi the bone-marrow . . . 

 into the circulation" (see Table 7.1) .f 



It appears evident, however, that these authors did obser\e some 

 of the facts of mitotic arrest. But not being histologists, they tailed 

 to appreciate the exact significance of the facts. In !*)()(). Dixon-" 

 wrote: 



A further effect of (okliicine is to excite karyokinesis. This action on the 

 mairow cannot be adequately determined at present, but it slioidd not l)e 

 regarded as specific to the leukocytes, but rather a type of the action wliich 

 goes on to a greater or less degree in other tissues of the body, but is 

 necessarily more easily in\estigated in the wanderin.s^ cells ol the blood. J 



*W. Dixoii anci W. Maiden. "Colchitine, With .Special Reference to Its Mode of 

 .'^.ctlon and Effect on Bone- Mai row," Jour. Physiol., 37 (HK)S) . p. 7.'i. 

 fibid., p. 62. 

 J W. Dixon, .1 Minutiil of I'liin iiuKology (London: Arnold, UKKi) , \y. 9(). 



