KINETIC JELLY 133 



Apart, however, from being able to measure the lives 

 of leucocytes, it is very necessary in this in-vitro work 

 to be able to tell at once when the cells with which 

 we are experimenting are alive, for it is essential that 

 one should deal only with living cells; hence w r e will 

 now give the formula for the preparation of a suitable 

 jelly which will excite amceboid movements in living 

 leucocytes. This jelly has been called for convenience 

 "kinetic jelly," for it will always excite living leucocytes 

 to activity. It is as well always to have a tube of it 

 ready to hand, in order that at any time a film may 

 be prepared, so that we may be able to make certain 

 that the cells in a sample of blood are alive. It is 

 prepared as follows: To a tube of 5 cc. of "coefficient 

 jelly" add five units (0.5 cc.) of Unna's stain, six units 

 of alkali solution (0.6 cc. of 5-per-cent sodium bicar- 

 bonate), and 0.7 cc. of a 1-per-cent solution of atropine 

 sulphate. The content of the tube is made up to the 

 total of 10 cc., with 3.3 cc. of water. The mixture 

 should be melted and boiled until it froths up in the 

 tube, and a drop of the stained jelly poured on to a 

 slide and allowed to set. A drop of fresh citrated 

 blood is then placed on a cover-glass, which is inverted 

 on to the film in the usual manner. It should be 

 examined at the room temperature, which may be said 

 to be about 18 or 20 C. 



When the cells come to rest on the jelly they will, 

 of course, be unstained. Slowly their granules begin 

 to turn red. A field which contains a few leucocytes 

 should be watched. In about fifteen minutes it will 

 suddenly be noticed that around the circumference of 



