274 COSTANTINO GORim 



lactic bacteria. On the contrary I have discovered that the 

 lethal temperature may reach 100°C. and sometimes still higher 

 values. 



My experiments have shown that this happens through the 

 formation of a sheath of coagulated casein in immediate contact 

 with the acid-rennin forming organisms. These findings allowed 

 me to explain the apparent failures in milk steriUzation, and they 

 furnish the basis for a betterment of the processes in use for 

 industrial milk sterilization. 



VISCOSITY IN YOUNG CULTURES 



Many lactic acid forming organisms are capable of inducing 

 ropiness in milk only during the early phases of incubation. The 

 property of making milk ropy, although recognized by various 

 investigators for the lactic acid bacteria, has not generally been 

 considered as a constant and essential character of this group of 

 organisms. In 1912 I first described a lactic acid bacterium 

 wliich constantly induced viscosity in milk, but only on the 

 inception of acidification and before the inception of coagulation. 



This organism at first induces ropiness, but the increase in 

 acidity of the medium and the increase in the firmness of the 

 coagulum soon obliterate this characteristic result of the growth. 

 When cultivated at a not too high temperature and on white- 

 sterile milk several other lactic organisms proved themselves, in 

 my hands, to possess this propert}^ The reason why many 

 investigators disagree as to the constancy of this rope-producing 

 property in many of the lactic acid bacteria is to be searched for 

 in its transitory manifestation. 



SPORE-PRODUCING LACTIC ACID BACTERIA 



In 1904 I studied a spore-forming bacillus from cheese and 

 described it under the name of Bacillus addificans-presamigenes- 

 casei, on account of its acid-rennet and acido-proteolytic charac- 

 ters and found it related to the subtilis or thyrotrix groups. 

 In 1906 I found in silage another similar form and described and 

 pictured it. Additional investigations have authorized me in 

 the assertion that this type is rather widely disseminated in milk 

 and dairy products and is therefore worthy of attentive study. 



