102 Mr. H. C. Koss. On a Coefficient of [Dec. 9, 



10 per cent., unity being - 8 c.c. The 10 c.c. of jelly contains this from the 

 outset. 



Heat, hastens diffusion. — Each unit 5° C. 10° C. is unity, 15° C. is 

 2 units, 20° C. 3 units, etc. For practical purposes I call 37° C. 7 units. 



Time, increases diffusion. — 10 minutes being 1 unit, 20 minutes 2 units, 

 and so on. 



Stain, Unna's polychrome methylene blue (Grubler), behaves as if it 

 increased diffusion.* — Unit - l c.c. 



Equations for ascertaining the Coefficient of Diffusion. — The nuclei of poly- 

 morphonuclear leucocytes recently shed from a healthy person, just stained 

 in 10 minutes when resting on a film of agar, 10 c.c. of which contained 

 - 2 c.c. of stain, 1 per cent, sodium citrate, 0"8 per cent, sodium chloride, and 

 6 units of sodium bicarbonate. The slide was kept at a temperature of 

 37° C. What was their coefficient of diffusion ? 



Then cf = that fx + h + t which just causes staining of the nuclei, 



but fx = (s + a)— (c + n) ; 



.-. cf= (2s+6a) + (7h + t)-(3c + n) = 16-4= 12. 



Where s is the unit of stain, a the unit of alkali, h the unit of heat, t the 

 unit of time, c the unit of sodium citrate, and n the unit of sodium chloride. 



The 10 c.c. of agar in this case was made up as follows: — 5 c.c. from the 

 original 50 c.c. of agar which contained sodium citrate 1 gramme, sodium 

 chloride 0'8 gramme, and citric acid - 083 gramme. The jelly was melted 

 and the following quantities of standard solutions added : 0'2 c.c. stain, 

 0"6 c.c. 5-per-cent. solution of sodium bicarbonate, and 4*2 c.c. water. 

 Total 10 c.c. 



The eosinophiles, however, did not stain under quite the same conditions 

 for it was found in the foregoing experiment that they were either achromatic 

 or ruptured. A fresh tube was made with 1 unit less alkali, when it was 

 found that the eosinophiles would just stain in 10 minutes. What was 

 their c/? 



c/= (2s+5a + 1h + t)-(3c + n) = 11. 



The lymphocytes, large and small, required 0"2 c.c. of alkali more than the 

 polymorphonuclear cells, the other factors being as before, what was their cf ? 



c/= (2s + 8a + 7h + t)-(3c + n) = 14. 



The foregoing tubes contained a very low content of stain, the chromatin 



* As already pointed out, stain should not be a unit of diffusion, for it is doubtful 

 whether it affects diffusion. It contains salts, and is alkaline when made, and alkalies 

 and salts are antagonistic. However, for reasons already given, it may be included in 

 the category. 



