THE PECTIC SUBSTANCES 73 



salts of organic complexes. The process of gelatinization 

 continues till the resulting jelly is of such a consistency as 

 to cease to flow in the viscosimeter, unless the condition 

 becomes complicated by the action of appreciable quantities 

 of electrolytes. 



The effect of this class of bodies appears to be the clump- 

 ing of the colloid particles by a metallic ion. By this 

 means, the amount of transformed pectin available for 

 meshwork formation is continually decreased. Thus the 

 maximum viscosity can never be as great in the presence 

 of any appreciable quantity of electrolytes as in their 

 absence. Whether any increase in viscosity occurs will, 

 according to this view, depend upon the relative rates of 

 pectin transformation and of clumping. When the former 

 preponderates the viscosity rises, but in time the two rates 

 become equal and the viscosity attains a maximum. The 

 downward portion of the viscosity curve is explained as 

 representing the progress of clumping at the expense of 

 the already formed network. When the clumps reach a 

 certain size they tend to unite into visible flakes, causing 

 discontinuity in the gel and consequent diminution in 

 viscosity accompanied by irregularity owing to the plugging 

 of the capillary. It may be seen that in the curves of 

 Fig. 3 this breaking up occurs usually when the viscosity 

 of the solution in the different experiments has about the 

 same value. 



By means of the above hypothesis given by Ball, the 

 interesting nature of the curves seems to be qualitatively 

 explained in a simple and rational manner, while at the 

 same time the need of further work is indicated. 



GELATINIZATION OF PECTIN BY ALKALIES. 



Contemporaneously with Ball's research, which was 

 completed in July, 1914, Haynes's study of the gelatiniza- 



