EXPERIMENTS WITH NUCLEIN 179 



From the foregoing facts, believing that it was 

 reasonable to suppose that chemical agents might 

 influence human cell-division, we resolved to try the 

 new in-vitro method. Bearing in mind that the cell- 

 proliferation of healing appeared to be associated with 

 the proliferation of cancer, our first step was to try the 

 effect of nuclein on leucocytes. A saturated solution 

 of it was made in "citrate solution," and this was mixed 

 with an equal volume of fresh blood. It was found 

 that the nuclein seemed to lower the coefficient of 

 diffusion of the cells very markedly compared with a 

 control experiment in which no nuclein was employed. 

 Some nuclein was then mixed up with jelly which 

 contained stain and which had the right index of 

 diffusion to stain leucocytes deeply, without killing them, 

 in twenty minutes. But nuclein did not excite amoe- 

 boid movements in the cells. 



In the next place some juice was squeezed from a 

 malignant growth and citrated, and the citrated mixture 

 was in its turn mixed with some fresh normal blood. 

 It was found that this juice, like the nuclein, lowered 

 the coefficient of diffusion of the leucocytes, but in 

 addition it excited amoeboid movements in them. 



The lowering of the coefficient of diffusion due to 

 nuclein was striking, because not only does the juice of 

 a growth do the same thing, but the cells of cancer 

 patients usually have a lowered coefficient. 



We were not satisfied, however, with this experi- 

 ment with nuclein, because the preparation of it which 

 we had obtained was very insoluble in neutral solution, 

 and it was impossible to employ it in any more concen- 



