42 ACTION OF AUXETICS AND KINETICS 



equal volume of this mixture placed on each. The 

 cover-slips were then applied to live slides, in the 

 one case (A) containing 0'2-per-cent. choline, and 

 in the other case (B) distilled water. Counts were 

 then made of the number of amoebae on each slide, 

 and were as follows, A 34 and B 26. After three 

 days a recount was made, and gave A 207 and 

 B 88. It is important to note that when a certain 

 strength of these auxetics and kinetics is exceeded 

 the amoebae are poisoned and multiplication is 

 retarded. There is thus an optimum dose for 

 each substance. Without making actual counts 

 it appears to us that the most effective mixture 

 to employ as an auxetic for amoebae is 0'4-per-cent. 

 creatine with 0'4-per-cent. choline. An apparent 

 increase was found with cadaverine and asparagin, 

 but possibly the best strength to employ has yet 

 to be found. With tyrosin there is a great increase, 

 the best strength to employ being a 0'01-per-cent. 

 solution, and the effect is further increased if an 

 equal volume of 0'02-per-cent. choline is added 

 to it. Tyrosin seems to take some time before 

 much increase is apparent, and this may be explic- 

 able by the abundance of binucleate forms pro- 

 duced by the auxetic, and by the fact, already 

 mentioned, that the amoebae under the influence 

 of tyrosin become on the average very much larger 

 than normal, many indeed being describable as 

 giant forms of the species. 



Thus, auxetics, and especially augmented auxetics, 

 undoubtedly in certain strengths cause great 

 proliferation of amoebae. 



Radiosa types. During prolonged work with 

 this amoeba, it was noticed that if the normal 



