42 



Prof. T. B. Wood and Mr. W. B. Hardy. [Oct. 24, 



the protein is charged positively ; when formed lay any alkali it is charged 

 negatively. 



It is interesting to note that, when alkali is added, it not only neutralises 

 any acid present, but also reacts directly with the protein as though the latter 

 were itself an acid. The alkali, therefore, disappears as such ; it is, in point 



1000 500 

 Fig. 2. 



of fact, neutralised by the protein with the formation of new ions. For 

 instance, in a particular hydrosol formed by carbonic acid, the particles of 

 gluten were charged positively, and had a specific velocity 46 x 10 -6 cm. per 

 second. Sodium hydroxide was added in quantity sufficient to make the 

 entire solution contain N/1600 of NaOH. The fluid was not alkaline to 

 phenolphthalein, but in spite of this the protein was now charged negatively 

 and had a specific velocity of 23 x 10 -6 cm. per second. 



Approximately pure gliadin, dissolved in 70-per-cent. alcohol, shows 

 relations to acid and alkali the same as those described for gluten. Dropped 

 into 98-per-cent. alcohol or distilled water, it forms an opalescence, and is 

 then electro-positive ; in presence of N/4160 of NaOH it is electro-negative. 



Conclusions. — The experimental results seem to prove beyond question that 

 the physical state of gluten — that is to say, the degree of coherence or 

 dispersion as a hydrosol, is determined by the potential difference between 

 the particles of the protein and the fluid. 



