2IO STANDARDIZATION OF PEPTONES 



Standardisation of the Peptone. Let us assume 

 that we have to deal with placenta peptone. This is 

 mixed with the serum of individuals, who are 

 certainly not pregnant, and then there should be no 

 alteration of the original rotation. Should this 

 not be the case, then the peptone is certainly not free 

 from sulphuric acid or barium. With the serum of 

 pregnant individuals a decomposition is bound to 

 take place. At first, readings are taken every hour, 

 and tests are made with many sera. A normal curve 

 for the peptone is constructed, from the separate read- 

 ings, by marking the angle of rotation on the abscissa 

 and the time on the ordinate (cf. the curves given 

 on pp. 62, 64, and 75-77). Once the normal altera- 

 tions of rotation of the serum peptone mixture are 

 known, then the readings for the diagnosis of normal 

 cases need only be taken every four to six hours. If 

 one has a special object in view, then the readings are 

 taken more often. 



The optical method supplements the dialysation 

 process in many directions. In the first place, it is 

 possible to determine quantitative differences in the 

 speed of the decomposition. Further, qualitative 

 differences may be observed. In the dialysation 

 process, on the other hand, the dialysate may 

 be used for experiments on animals and, for 

 instance, be injected, in a state of concentration, 

 for the purpose of 'deciding, whether : certain 



