CELL-DIVISION RESTRAINED 377 



actually has the power of preventing the "natural" 

 auxetics from inducing cell-division; but it has no 

 inhibitory action against atropine or azur dye. The 

 restraining power of serum can be measured as shown, 

 and it is possible that this power varies with individuals, 

 a point which remains to be determined. 



It was also ascertained that the restraining body 

 in serum does not combine permanently with the 

 auxetic and so prevent its action. Jellies were pre- 

 pared with suprarenal extract with kreatin and choline, 

 which induced divisions in lymphocytes. The right 

 amount of serum was added to them just before the 

 jellies cooled, and it was noted that they stopped the 

 auxetic action of the jellies. The same jellies were 

 then boiled and the serum proteins precipitated. On 

 making specimens again from these jellies, it was now 

 found that their auxetic power was re-established. 

 Hence it is obvious that the restraining body in serum 

 is not thermostable. 



Lastly, it was found out that 1 cc. of serum con- 

 tained in 10 cc. of jelly which also contained 1 cc. of a 

 1-per-cent solution of choline stopped the kinetic ac- 

 tion of the latter in exciting amoeboid movements in 

 leucocytes. If the jelly was boiled, however, the action 

 of the choline was restored. 



These experiments are very constant in their results. 

 Careful controls were made throughout. We think 

 that by means of them the restraining power of 

 different sera could be measured with a certain amount 

 of accuracy. What the nature of the restraining body 

 in serum is we have no opinion to offer. It should be 



