DIRTY MILK' 67 



mittee would suggest that a standard disk of an inch in diameter be 

 selected for the filtering of a quart of milk, and a proportionate- 

 sized disk for smaller amounts of milk. The Lorenz apparatus 

 is simply a convenient filter for filtering milk through a cotton 

 disk; but various other types than that distinctly known by this 

 name are equally satisfactory. A Gooch crucible may be used 

 conveniently, or any other device in which the cotton disk is sup- 

 ported upon a gauze and in such position that milk can be readily 

 filtered through it. To be most efficient, the cotton disk should be 

 subsequently dried and sent to the individual dairyman. In order 

 to have the best results, the most desirable plan is to do the filter- 

 ing in the dairy immediately after milking. For this purpose bat- 

 teries of filters are needed, and these must be warmed in cold 

 weather, in order that milk should pass through them readily. 

 If these are used in the dairy, the results thus demonstrated to the 

 dairyman are very convincing. The test is quick and simple and 

 is proving very useful in locating unclean methods. It is much 

 less cumbersome than the somewhat more expensive method of 

 measuring the amount of dirt, and, although it does not give a 

 quantitative but only comparative results, it is as useful for the 

 purpose of detecting and remedying unclean conditions as the 

 more slow and more expensive quantitative methods. 



From these data the committee would present the following 

 recommendations : — 



1. The microscopical examination of raw milk, either by the 

 centrifugal method or the direct examination of milk, gives very 

 valuable information, since it presents in a few moments a graphic 

 picture of the bacterial content as well as the number of cells, and 

 offers a prompt method of excluding some samples of milk which 

 are manifestly unfit for use, doing this promptly. To give the 

 most valuable results, the committee would recommend the use 

 of some good blood stain like the Jenner or the Wright stain. 



2. Because of the irregularities in methods and results, no 

 standard can yet be given for grading milk by the microscopic 

 examination. Special attention is recommended to the presence 

 of polymorpho-nuclear neutrophilic cells. A high cell count 

 alone is not sufficient to condemn milk, but, if accompanied by 

 chain-forming streptococci, it is an indication of udder troubles. 

 The presence of streptococci alone is also sufficient to suggest the 



