BACTERIAL MILK ANALYSIS 249 



Since, however, evidence already collected warrants, 

 beyond all question, the general statement that these 

 cells frequently do not have the significance that has 

 been attached to them by many observers, it would per- 

 haps be more fair to all parties concerned to use this 

 test at present as a means of detection only, and 

 not condemn the supply unless physical lesions are 

 demonstrated. 



We are not prepared at this time to recommend 

 a numerical standard to serve as a basis for such in- 

 spection. Milk having a high cell content should, how- 

 ever, be regarded with suspicion. Such milk should be 

 traced to its source and the cow yielding it excluded 

 or kept under close observation if not showing definite 

 physical lesions. 



The two methods for the determination of leucocytes 

 in vogue, (1) smeared sediment, (2) volumetric, have 

 each their advocates according to the view point of the 

 worker, and each possesses in its distinctive sphere 

 points of advantage which cannot be ignored. The 

 volumetric method may be further subdivided, some of 

 the methods devised being quantitative only, while 

 others are qualitative as well. 



The standards so far chosen have been more or less 

 arbitrarily selected on what appears as rather inade- 

 quate data, and from a comparison of results it is 

 apparent that much more comparative work needs to 

 be done. 



So much has been published descriptive of these 

 various methods that references only can be given here. 



The smeared sediment method has been most used 

 for city inspection work or work of that character where, 

 through examination of many specimens, undesirable 

 sources of supply may be cut off. 



Its advantages along this line are : 



1. Smallness of sample seized, 10 c.c. being ample 

 for all necessary tests, including bacterial count, leu- 

 cocyte and streptococci estimations. 



2. Rapidity of operation, exact counting being un- 

 necessary in routine work, and as has. been proved 

 through thousands of tests, nine out of every ten 

 samples being practically free from suspicion. 



