272 COSTANTINO GORINI 



liquefaction of the casein coagulum. I have described, as organ- 

 isms possessing acido-rennin properties, cocci from the udder of 

 the cow, and bacilli from cheese and fermented milk beverages 

 such as Yoghurt and Gioddu. The inception of casein break- 

 down is dependent upon various circumstances; chief among 

 these, and of paramount importance, is temperature. 



In 1897 1 demonstrated that while high temperatures are appro- 

 priate to the process of lactose fermentation, lower temperatures 

 are more appropriate to the cleavage of casein, and in several 

 additional pubUcations I was able to verify my findings. Finally 

 in 1915 I presented analytical data bearing upon the behavior of 

 lactococci and lactobacilli at temperatures ranging between 25° 

 and 35°C. and 15° to 20°C. Many lactic acid forming bacteria 

 which failed to show lacto-proteolytic properties when cultivated 

 at the higher temperatures were found to possess these properties 

 when cultivated at the lower temperatures, i.e., such tempera- 

 tures as prevail during the process of cheese ripening. 



Another condition of great importance for the furthering of 

 the lacto-proteolytic activities is the composition of the medium. 

 Already in 1902 I had advanced evidence as to the influence 

 of the nature of the protein upon the activities of the organisms, 

 indicating that while among the udder cocci some dissolved casein 

 as well as gelatin, others only dissolved casein while again others 

 were found that acted only on gelatin. 



Another factor of great importance was found to he in the 

 quality of the milk itself, which presents great fluctuations the 

 causes of which are to be found in the changes it undergoes pre- 

 vious to reaching the laboratory (besides the influence exerted by 

 the race of the animals furnishing the milk, their physiological 

 state, their feeding regime, etc.) or in the laboratory itself. In 

 addition, in 1915, 1 was able to show the noxious influence exerted 

 by the peptonized constituents of the milk derived from the 

 casein cleavage. These constituents are often to be found in 

 miUc, especially in market milk, and are due to the great develop- 

 ment of organisms before steriUzation. 



Another factor of great importance, and indeed of an essential 

 character in the behavior of milk, is to be found in the method of 



