40 DIVISION OF FLOATING CELLS 



solution, provided that solution receives a supply 

 of the necessary chemical auxetic. 



A good auxetic jelly should he prepared, such 

 as that described in the last paper, or a similar 

 jelly containing acetamidine in the same strength 

 as and instead of the theohromine will do equally 

 well. Putrid suprarenal extract is also a very 

 good excitor of cell-division. 



The jelly is melted and a small quantity of it 

 poured into a narrow test-tube, which is stood 

 upright at the room temperature while the jelly 

 sets at the bottom of the tube. The upper surface 

 of the set jelly, of course, is concave. 



In a capillary tube, a volume of a solution 

 containing 3-per-cent sodium citrate and 1-per- 

 cent sodium chloride is mixed with an equal 

 volume of blood drawn from the finger. Two 

 small drops of this mixture are carefully allowed 

 to fall on to the cup-shaped surface of the jelly in 

 the tube. A plug of wet cotton- wool is placed 

 within the mouth of the tube to saturate the air in 

 it in order to prevent evaporation, and the tube is 

 corked up. Lastly, the tube is placed upright in 

 the 37 C. incubator for three-quarters of an hour. 



On removal from the incubator, it will be seen 

 that the corpuscles have sunk towards the bottom 

 of the citrated plasma in the cup-shaped surface 

 of the jelly. By gently shaking the tube, the cor- 

 puscles and fluid are again mixed up. With a 

 narrow pipette, this mixture can be removed, and 

 if a drop of it is examined microscopically between 

 a cover-glass and a slide, many of the lymphocytes 

 will be seen to be floating about undergoing the act 

 of mitosis. The auxetic substance diffuses from 



