788 



Colchicine 



mentioned that colchicine increased the numbers of Ieukoc\tcs. No- 

 body appears to have been interested enough to study more precisely 

 the bone-marrow changes, and it is only in 1934 that this T\as done.^''' 

 Colchicine-mitosis -was then disco\ered at once, lor in the laljoratory of 

 A. P. Dustin, Sr., problems of mitosis and mitotic stinudation had been 

 studied for many years, and the proper technicjues had been de\ eloped. 



TABLE 7.1 



Effect of Colchicine on Blood Count in Rabbit* 

 (Injection with 0.02 gm. colchicine made at 1 :05 p.m.) 

 (After Dixon and Maiden) 



Cellular Types 



Time of Blood Count 



1 P.M. 



Total leukocytes per cmm. 



Granulocytes (%) 



(pseudoeosinophils) 



Eosinophils. 

 Mast cells . 



Myelocytes . . 

 Monocytes . . 

 Lymphocytes . 



Erythroblasts 



(per cent leukocytes) 



8850 



37 

 1 



10 

 45 



1:30 



3:00 



4600 



16 

 1 

 4 



4 



75 



6700 



50 

 1 



7 



3 



7 



32 



5:00 



9:15 



9650 



36 

 0.5 

 6.5 



7.5 

 4.5 



45 



20,000 



16 

 1 

 1 



7 

 4 



71 



41 



* Weight of rabbit, 1800 gm. 



\\'hile the changes occurring in the blood-forming tissues were 

 then described, first in mannnals,^' then in amphiljia,!' the Dixon 

 and Maiden experiments were repeated in rabbits by another author, 

 unaware of the problems of mitotic regulation and poisoning. i'' The 

 effect of repeated small (from 1 to 5 mg.) daily injections was studied. 

 Immature white and red blood cells were foiuid in the blood stream. 

 The percentage of hemoglobin and the number of red blood cells 

 progressi\ely decreased. The marrow was ver)' cellular, ^vith leukoblas- 

 tic areas far in excess of the erythroblastic ones. The following con- 

 clusion was reached, to cjuote: "Colchicine, undoubtedly, stimulates 

 the formation of new cells in the marrow, and induces immature 

 cells ... to apj^ear in the peripheral blood, but . . .its destructi\e po^vers 

 outweigh its stimidant effect. "* Here again, the action on the mitotic 

 spindle was missed.^" 



*C. R. Das Gupta, '" Ihe Action of Leiicopoietic Driii;s," Indian Jour. Med. Res., 

 26 (1939) p. 997. 



