532 



STATE BOARD OF AGRICULTURE. 



III. THE CHANGES PRODUCED IX MILK I5Y GLltM U. 



It has been demonstrated fully that some product or products manufactured 

 by germ B, while growing in milk are responsible for the favorable influence 

 upon germ A; it has also been shown that these products are thoroughly stable 

 when subjected to discontinuous sterilization, and. further, when these products 

 after complete sterilization are added to sweet milk, curding may be produced. 



To determine what these products are is a difficult task, and we are still in 

 the dark concerning them, yet by studying this subject from the synthetic and 

 analytic standpoints, a little knowledge, at least, is gained. 



Suspecting that through the rapid digestfon of milk by germ B there might be 

 digestion products corresponding to other products already known upon the 

 market, an effort was made to furnish such a product by simple addition to milk, 

 bouillon and agar. These preparations used did not prove a success and none 

 even approached an agar, made from the actual products of germ B, placed in 

 milk for the cultivation of germ A. Improvement in the growth of germ A 

 was obtained by the addition of certain substances it is true, but all fell so 

 far short of what really occurs in the presence of germ B or its products that 

 little attention was given them. 



The changes produced by germ B, visible to the naked eye, may be noted 

 from time to time. At first there is a yellowish, watery layer seen upon the 

 surface of the milk, a complete digestion, of the casein. This process continues 

 downward until the entire milk is practically peptonized. The proteolytic 

 capacity of the germ is marked by rapid progress under the most favorable 

 conditions. As the culture ages the pigment changes to orange yellow and 

 the consistency of milk is slimy. The culture is turbid and alkaline. The odor, 

 which is very strong, is perceptible as soon as the germ starts. At first it is 

 cheesy, passing to pineapple, and then, in old cultures, to a putrid character. 

 These visible changes in culture and the pronounced change in odor would 

 indicate a continuous change in products during the process of degradation 

 of the proteid substances of milk. 



To arrive at a suggestive knowledge of the changes wrought by germ B in 

 milk, analyses of cultures at different ages were undertaken after the usual 

 methods. It is of course understood that while our knowledge of the proteid 

 constituents of milk and their degradation is so incomplete and also of the 

 methods employed for estimation so unsatisfactory, the results secured should be 

 regarded as indicative rather than absolute. 



Total nitrogen 



Casein 



Albumin 



Caseoses, peptones, etc 



Amide compounds 



Ammonia 



Percentage of Nitrogen. 



II. 



Total nitrogen 



Casein 



Alhumin 



Casefiscs, peptones, etc 



Amido compounds 



Ammonia 



