42 Notes from the Physiological Laboratory 



VII. 



ON THE DIGESTION OF RAW AND OF 

 BOILED MILK. 



DK. N. A. RANDOLPH referred to certain pro- 

 found changes produced in milk by boiling. In 

 this operation the casein is not coagulated, but there 

 is an evolution of sulphuretted hydrogen (Schreiner), 

 a diminution in the gaseous constituents of the fluid 

 and a change in the amount of ozone present. 



The most striking difference between raw and 

 boiled milk lay in their respective responses to 

 rennet and acids. 



At the body-temperature the firm coagulation of 

 raw milk occurred almost immediately upon the 

 addition of a neutral rennet solution, whereas boiled 

 milk, under the same conditions, did not clot for a 

 far longer period, and the coagula were not firm. 

 On the other hand, dilute or strong acids were ten- 

 fold as active upon boiled as upon raw milk. Some 

 time after making these experiments Dr. Randolph 

 found that so far as acids and rennet were con- 



