4] 



TONOTAXIS 



91 



were repelled. The numbers at the heads of the columns are 



the different values of n in the formula, 



n 



1000 



MW%. Since 



the different solutions were made up on the basis of molecular 

 weights, all solutions of a given concentration contained the 

 same number of molecules. 



TABLE XII 



From this table it appears that, as a rule, solutions of 

 MW % and over are repelled, while those of YoVo or 

 except in the case of KCN, permit the free migration of the 

 bacteria into the tube. 



In the case of those substances whose isotonic coefficient is 

 4, solutions of y^ MW % and over always repel, and those of 

 yoVo in the majority of cases permit free migration. In the 

 case of those substances whose isotonic coefficient is 2, solutions 

 of over Y^-Q- MW % repel, and those of under y^ usually 

 permit free migration. The solutions at which repulsion just 

 occurs in the three cases are in the ratio 10 : 7 : 6 ; which is 

 nearly the same ratio as the reciprocals of the isotonic coef- 

 ficients, which, multiplied by 2 run, 10:6.6:5. Thus the 

 conclusion seems justified that the repelling action of these 

 substances is proportional to their isotonic coefficients, and is, 

 therefore, probably osmotic in its nature. 



In a second work, MASSART ('91) has studied this matter 

 with the aid of new methods. A drop of sea water containing 

 bacteria is prepared as before, on a cardboard ring, but, in place 



