132 



PHYSIOLOGY OF ALIMENTATION. 



With the use of such an instrument SPRIGGS found that 

 during digestion the viscosity of a solution of a coagulable 

 protein gradually decreases. This decrease in viscosity 

 corresponds with a chemical change in the protein undergoing 

 digestion from the state in which it is coagulable by heat 



2 



Hour 



(6) 



FIG. 19. 



into that in which it is not coagulable by this means, in 

 other words (to speak not very accurately), from the albu- 

 mins into the peptones. 



If the change in the viscosity of the protein undergoing 

 digestion is expressed in the form of a curve, one similar to 

 that shown in Fig. 19 (6) is obtained. As can readily be seen, 

 the viscosity of the protein solution decreases at first very 

 rapidly, later more slowly, until finally it runs almost parallel 

 with the base-line. When this line of unchanging viscosity 

 is reached, the larger part of the coagulable protein has 

 been converted into the uncoagulable. 



