THE MANUFACTURE AND HANDLING OF BUTTER. 245 



in the outer layer. In the centre of the tub a compara- 

 tively small increase took place during the first hours, but it 

 soon stopped, at least if the butter had been well worked. 

 The lively bacterial increase in the surface layer spread 

 very slowly toward the centre. 



Lafar (Munich) found an immense number of bacteria 

 in sour-cream butter examined by him, which presumably 

 had not received the best treatment. In most samples ten 

 to twenty million bacteria per gram (% of an ounce) were 

 found, and he adds that it is not stretching matters to 

 assert that more living organisms are often consumed with 

 an ordinary good-sized sandwich than there are inhabitants 

 in Europe.* 



The outer layers of fresh sour-cream butter will be 

 found to contain a large number of the bacteria that took 

 part in the ripening. But these do not generally appear 

 to thrive long in butter, unless it is soft and contains 

 a good deal of buttermilk. Samples of butter of different 

 origin have shown great difference in this respect. If a 

 sample is dry and hard, the lactic-acid bacteria and even 

 some putrefactive bacteria will soon disappear, so that but- 

 ter after four or five days will present an entirely different 

 picture to the bacteriologist than before. In place of the 

 staff-like bacilli found, other wholly different forms seem 

 to appear, such as several kinds of sarcina and small 

 micrococci. These forms multiply rapidly, and according 

 to what I have been able to find out, do not in general 

 exert any bad influence on the quality of the butter at 



* Sigismund (Inaug. Dissert. Univ. Halle a. S., 1893) found from 

 26,000 to over 2,000,000 bacteria per gram in eight samples of 

 Halle butter. W. 



