534 



STATE BOARD OF AGRICULTURE. 



into dextrins* but had not produced any reducing sugars.! Tliere was no gas 

 formation in any of tlie cultures. These facts help to confirm the view that no 

 acid is formed at any time during the development of the culture. In the 

 chemical analyses of cultures of germ B there is every evidence to believe that 

 no formation of acid occurs because of the constantly increasing amounts of 

 amido and ammonia compounds occurring right on the start. The forty-eight 

 hour culture showing reddish blue litmus, is represented in our analyses, and 

 these results would assist greatly in clearing this field. It is also significant 

 to note the character of the germs which besides germ B are capable of yielding 

 about the same influence upon the lactic germ A. By summing up, the entire 

 field is presented in a few words: 



1. Litmus during the first few hours is changed to a muddy, reddish blue, 

 then completely reduced. 



2. Phenol-phthalein is in some manner affected by the products of germ B 

 in milk culture, and partly destroyed. 



3. Other indicators tested have no higher value in this work than litmus and 

 phenol-phthalein. 



4. Old milk cultures of germ B are decidely alkaline. 



5. In saccharine bouillon cultures there is an increased alkalinity, with the 

 exception of levulose. 



G. Starch is changed to dextrins, but no reducing sugar is formed. Reaction 

 is not altered. 



7. In milk-cultures by analysis, increasing amounts of amido and ammonia 

 compounds are produced. 



8. Other known germs of the same character are capable of causing practically 

 the same action, varying in degree of intensity, and no acid constituent has been 

 recognized among their products. 



9. The curding effect this germ sometimes possesses has now been traced to its 

 products, which are decidedly alkaline, especially in old cultures. This was 

 the strongest argument for a long time in favor of acid production, but is not 

 tenable after showing the products will curd milk. 



The author has felt constrained to present the matter of acid formation very 

 fully because unless the reader has it clearly in mind, there is a possibility of 

 being misled. The one strong factor which would not allow the author to reach 

 a very definite conclusion in regard to all milks early in these investigations 

 was the occasional curding of milk by germ B before complete peptonization. 

 After demonstrating that the products apart from acid or enzymes could do this, 

 no further trouble existed in believing that there is no acid formation on the 

 start followed by alkali production, but that the alkaline reaction increases 

 steadily from the beginning and continues for some time. 



v. THE EXTE.XT OF ASSOCIATIVE ACTION IX THE SOURING OF MILK OR THE INFLUENCE 

 OF OTHER GERMS THAN GERM B UPON GERM A. 



This phase of the subject might be carried on indefinitely, if worked out in 

 detail. The writer has been so fully occupied with germs A and B that he 

 has not been able to get far beyond, still he has made an attempt to extend 

 the studies to other associations, in all of which germ A figures as the lactic 

 germ, but some other micro-organism has been substituted for germ B. Mr. 

 F. B. Howard has assisted with germs 12100 and Proteus vulgaris. 



GERM 12100 AND GERM A. 



Culture. 



Age of culture 



Temperature maintained. 



Acidity 



Clmracti.T of culture 



Count of micro-organisms 



•Smooth, tliick lopper. tLoppered and whey separated. 



•Iodine was used as ordinarily for this determination. 

 tFchling'a Solution was employed. 



72hrs. 

 23° C. 



05° 



* 



704,000.000 

 per c. cm. 



12100 + A. 



72 hrs. 

 23° C. 

 80°^ 

 t 

 910,000,000 

 per c cm. 



