STANDARDIZATION OF PEPTONES 



from the other, as decomposition begins, and 

 manifests itself for a certainty, only after about six 

 hours. Readings should not be followed up for more 

 than thirty-six to thirty-eight hours. 



Great progress would be made, if the reading of 

 angles of rotation could be taken by means of some 

 kind of automatic device. Objective values could be 

 obtained, and we should be in a position to follow 



FIG. ii. 



up details which, during the long intervals between 

 readings, at present escape observation. Experi- 

 ments in this direction, with the collaboration of Dr. 

 Wildermuth, are in progress. 



To obviate the cooling of the polariscopic tubes, 

 during polarization, tubes have been constructed with 

 water jackets (fig. n). Lately, an electric heating 

 apparatus 2; has been added to the polariscope itself. 



23 Emil Abderhalden : " Ueber eine mit Polarisations- 

 apparat kombinierte elektrisch heizbare Vorrichtung zur 

 Ablesung und Beobachtung des Drehungsvermogens bei 

 konstanter Temperatur. Zeitschr. f. physiol. Chem., 84, 300 

 (1913). 



