BACTERIOLOGICAL ANALYSIS OF BUTTER OR CHEESE. 283 



large a number of bacteria may be consistent with whole- 

 someness of the milk, so long is the quantitative analysis of 

 milk by health boards a matter of doubtful value. In the last 

 year or two the problem of a bacteriological oversight of the 

 milk supply has been agitated in various places, and it seems 

 at least probable that the development of the methods of in- 

 spection will in future demand a more careful study of this 

 problem. If it should be practical for health boards to detect, 

 by means of a differential analysis, the types of bacteria in 

 milk, it may prove that this method of analysis of public milk 

 supply will give important data for regulating this extremely 

 valuable food product. At the present time, however, the 

 condition of our public statutes is not such as to have made 

 a bacteriological analysis of milk by health boards a matter 

 of much importance, and nowhere has this analysis been 

 turned to much practical use. 



ANALYSES OF BUTTER OR CHEESE. 



In making bacteriological analyses of these products the 

 methods above described are used with slight modifications. 

 The number of bacteria is given per gram rather than per 

 c.c. To make the tests, a small, accurately weighed bit of the 

 material (butter or cheese) is used. If it is butter it may 

 be placed in melted gelatin, and then, by proper agitation, 

 distributed through the culture medium. The rest of the 

 details are the same as with milk. In the analysis of cheese 

 there is some difficulty in getting the cheese finely enough 

 divided to distribute the bacteria uniformly. It may be 

 accomplished as follows : A small bit of the cheese is removed 

 with a sterilized knife and placed in a tube containing a 

 known .quantity of melted gelatin. The weight of the tube 

 before and after this addition gives the weight of the cheese ; 

 or this bit of cheese may be weighed directly upon a bit of 

 sterilized paper. With a sterilized glass rod the bit of cheese 

 is thoroughly rubbed up with the gelatin to make a uniform 



