DAIRY FARMING DAIRYING. 483 



that rodiK'inji: substances linvc been formed dnrinji the storin;,'' iind that our 

 results do not give the correct amount of lactose." 



The percentaj^e of total nitrogen increased a little, due lo the loss of water 

 that carried away the soluble substances, the nitrogenous material being in 

 large part insoluble. In the average of all samples the total nitrogen in fresh 

 butter was 0.072 per cent, for that stored 100 days 0.0745 per cent, and for that 

 stored 250 days 0.075 i)er cent of the weight of butter. 



The salted cold samples showed a comparatively slight increase in amid 

 nitrogen. In the unsalted cold and salted warm samples the increase was 

 slightly larger, while in unsalted warm samples it rose to from 20 to 30 per 

 cent of the total nitrogen. Samples from the creamery with the highest scored 

 butter had the least change. The lots scoring a little lower and made from 

 a low quality of cream had an increased degradation of protein, while the 

 butter with the lowest score yielded the largest amount of proteid cleavage 

 pi'oducts. 



The compounds of nitrogen not precipitated by copper sulphate and also those 

 not precii)itateil by phosphotungstic acid increased gradually as the butter was 

 kept in storage. Those not precipitated by tannic acid increased and after a 

 time decreased, but not below the initial amount. It is pointed out that possibly 

 butter proteins in the course of degradation pass from a form that is not 

 precipitated by tannic acid into a form that is i»reclpitated but then again into 

 a form not precipitated. 



At short Intervals the micro-organisms in the butter were counted according 

 to the types of colonies. Only 4 species. occurred with remarkable frequency, 

 viz, lactic-acid bacteria, 2 yeasts, and OiOium hictis. The 2 yeasts were the 

 same as those in the ])reliminary investigations designated " rapidly liquefy- 

 ing" and "small irregular" yeasts. The lactics decrease<l from the first day 

 of storing, at first rapidly, then more slowly. In accordance with the previous 

 year's investigations, the decrease in the cold storage sani])les was larger in 

 the unsalted samples. Above the freezing point, however, the two ran parallel, 

 the unsalted samples having at all times about twice as many bacteria as the 

 salted ones. 



The li»iuefying yeast occurred frequently in the butter from two of the 

 creameries, while in all the .34 investigations of the butter from the other 

 creamery it was found only 5 times. It did not increase except in the unsaltetl 

 samples at +G°. The nonliquefying yeast showed an increase in all butters, 

 the numbers never very high but with a pronounced increase at all times. 

 The unsalted warm samples had the highest counts, these amounting to 10 

 per cent of the lactic-acid bacteria. This yeast was not found in fresh butter 

 and appeared on the plates only after about 10 days, 0. lactis showed an 

 increase in the unsalted samples but not in the salted. 



Pure cultures were made with agar plates containing brine to ascertain which 

 micro-organisms were able to multii)ly in the salt concentration usually found 

 in butter. On a 12 per cent salt agar there was a good growth of various 

 organisms. The bacteria did not thrive well, while the 2 yeasts grew abun- 

 dantly, the liquefying yeast appearing in about 2,000 cells and the nonliquefying 

 in about 30,000 cells per gram of butter. O. lactis was found in about the same 

 number as the nonliquefying yeast. After 3 months of storage the butter was 

 l)lated in a 24 per cent salt agar and 20,000 cells of the nonliquefying yeast were 

 found per gram of butter. Other cultures showed that the resistance of the non- 

 liquefying yeast to unfavoi-able conditions as salt and cold, and even with the 

 two combined, is remarkable. It was able to thrive at a temi)erature of — 6°, 

 <nen though its growth was retarded by salt. " Whether this yeast has any- 

 thing to do with the off tlavor of cold storage butter is questionable. It occurs 



