232 BIO-CHEMICAL JOURNAL 



NOTES TO TABLE OF DYES 



The molecular weight ot methyl-violet is given as that of the penta-methyl derivative. 



Diffusion. The words 'very slow' mean that a certain amount had passed through 

 parchment paper by the end of 24 hours. . 



The statements as to the ultra-microscopic behaviour of dyes in the column headed 

 ' Size of particles ' are taken from the work of Michaelis referred to in the text. 

 ' Sub-microscopic ' means that the solutions are resolvable into particles. 

 ' A-microscopic ' means that they are optically homogeneous. 



Electric migration. It was difficult to be certain in the case of methylene blue since 

 bleaching occurred by the electrolytic chlorine. 



The measurements of electrical conductivity were taken 3139 C unlessotherwisementioned' 

 They are not to be looked upon as absolutely correct, since the dyes were not 

 specially purified, except the eosin methylene-blue compound. 



State of solution. It is impossible to make definite statements as to certain dyes, f.g., 

 eosin, since they have some properties of colloids, but not all. 



The columns headed ' Rations ' and ' Anions ' refer to the action of these bodies on 

 adsorption by paper. It is to be understood that in all cases the action of Anions 

 is very much less than that of Kations. 



The columns 'Negative' and 'Positive colloid' refer to actual precipitation, not 

 adsorption. 



The column ' Stable colloid ' refers to the effect of this on the facilitation or inhibition 

 of adsorption by kations. 



