642 CASEIN VISCOSITY STUDIES 



the data for G dissolved in NaOH are included, since G seemed to 

 conduct itself in all respects similar to R. All the pH values are the 

 result of electrometric determination. Fig. 3 contains the viscosity- 

 pH curves of the four hydroxides studied. 



Fig. 3. Viscosity-pH curves of casein dissolved in the respective alkalies. 



There are two noticeable characteristics among the various curves. 

 In the proximity of pH 9.0 the different alkalies reach their maxi- 

 mum viscosity with casein. This is so uniform that we are safe in 

 saying that casein shows its maximum viscosity at this reaction except, 

 as the data in Section II will show, when it is dissolved in the presence 

 of certain anions such as borates. The magnitude of this maximum 

 viscosity varies somewhat with the alkali, being greatest with NPI4OH 

 and least with LiOH, though the difference is apparently of little 

 immediate importance. 



