376 PREVENTION OF PROLIFERATION 



the serum in this and the subsequent experiments, the 

 serum was added to the jelly after the latter was boiled 

 and before it had cooled to such an extent as to prevent 

 it setting on the slide. It was found that the serum 

 did not prevent the cell-division induced by the azur 

 stain. 



The experiments were then repeated with a jelly 

 which contained suprarenal extract, but no stain or 

 atropine. The jelly was first tested, and mitotic figures 

 induced in lymphocytes with it. The jelly contained 

 0.2 gramme of suprarenal extract, and it was found 

 that if it also contained 0.5 cc. of serum the auxetic 

 action of the extract was not stopped; but if it con- 

 tained 2 cc. of serum the auxetic action of the 

 suprarenal extract was completely inhibited. 



The experiments were then repeated with an auxetic 

 jelly composed of a mixture of 1 cc. of a 1-per-cent 

 solution of kreatin and 1 cc. of a 1-per-cent solution 

 of choline; and it also contained 10 units of alkali 

 solution. With this jelly it required the addition of 

 2.5 cc. of sheep's serum, to prevent it causing cell- 

 division. 



Using human serum, it required 2 cc. of it to stop 

 the action of . 2 gramme of suprarenal extract by itself. 

 1 cc. of serum will stop the action of the combination of 

 .0.01 gramme of kreatin and 0.01 gramme of choline; 

 1 cc. of human serum will stop the action of . 5 cc. of a 

 2-per-cent solution of globin which had been allowed 

 to become putrid, and which would, by itself, induce 

 division in lymphocytes. 



Hence it is apparent that normal blood-serum 



