106 



Mr. H. C. Ross. On a Coefficient of 



[Dec. 9, 



nuclei will stain in the given time. By this means death is not necessarily 

 involved. 



Example to show that the Diffusion of Substances other than Stain may be 

 Dependent on the Coefficient of Diffusion of Cells. — Given eosinophils have 

 a cf of 11. They are resting on agar which contains the usual quantities of 

 sodium citrate and chloride, viz., 3 and 1 imits respectively, but it also 

 contains O02 gramme of sodium bicarbonate (4 units), - 6 c.c. of stain, and 

 - 007 gramme of atropine sulphate. The fact that a mixture of atropine 

 and methylene blue will excite a remarkable exaggeration of amoeboid move- 

 ment in leucocytes has already been published (5). How long will it take 

 to produce marked exaggerated movements in the given eosinophiles at 

 a temperature of 20° C. ? 



Then, since it is necessary for the given cells to be alive at the expiry of 

 the time required, 1 digit must be subtracted from their cf — 



t = (10ef+ 3c+n + 0-ffis) - (6s +4a+ 3h), 

 t = 1*5 units of time or 15 minutes. 



Where z is the unit of at^Dpine sulphate, 0"013 gramme. A 1-per-cent. 

 solution was found convenient as a standard, and 0"7 c.c. was used. 



The Coefficient of Diffusion may be resolved into the Value of any one of the 

 Units. — Since by the foregoing equations any one of the units can be 

 resolved into the value of any one of the other units which go to make 

 the fx, and since fx + h + t = cf, therefore any cf can be expressed in the 

 value of any of the units ; into alkali for instance. But the unit of alkali is 

 5 milligrammes of sodium bicarbonate. Consequently the coefficient of 

 diffusion of the bacteria contained in the growth of Bacillus typhosus, used in 

 one of the examples, may be said to be equivalent to the alkalinity of 

 105 milligrammes of sodium bicarbonate. 



Summary and Suggestions. 



The difficulty has been in the construction of the units. So far I have 

 found them to be sufficiently accurate for practical purposes within the 

 compass of these experiments, of which a very large number have been 

 made, extending over a period of several years, involving the use of many 

 varieties of cells. 



The determination of the coefficient of diffusion is brought about by 

 allowing living cells to rest on a jelly which contains stain. Several factors, 

 some of which may be contained in the jelly, hasten or delay the diffusion of 

 the stain into the cells, and the coefficient of diffusion is the sum of the 

 factors which causes the stipulated staining of the cells added to the amount 



