New York Agricultural Experiment Station. 27 



sufficiently favorable results to justify the publication of two pre- 

 liminary bulletins which are numbered 373 and 380 respectively. 



Microscopical examination of milk for bacteria. — Bulletin No. 373 

 discusses the usefulness of the microscope as a means of determining 

 the number and the general character of the bacteria present. This 

 bulletin likewise gives a comparison between the results secured 

 with the new method and those secured with the older, and more 

 generally used, cultural methods. The new method promises to be 

 of great value as it is scarcely more difficult to carry out than the 

 well known Babcock test for butter-fat and apparently gives fully 

 as accurate and as usable information in the case of raw milk as 

 do the cultural methods. It likewise has a practical advantage 

 over any cultural method in that the results are almost instantly 

 available so that, if desired, the bacterial quality of a given sample 

 of milk can be determined before it is used. Cultural methods of 

 determining milk quality require from several hours to five days 

 before results are available. By the use of the microscope, raw 

 milk can be readily separated into as many as three grades, and 

 the cost of making the test is so small that it should find general use 

 in the hands of milk dealers. They can use it in this way to control 

 the bacterial quality of the milk which they handle as readily as 

 they can control its butter-fat. 



Cells in milk derived from the udder. — Bulletin No. 380 gives the 

 results of studies on the tissue cells in milk which have been made 

 by the use of the technique discussed above. These results have 

 a bearing upon some of the problems involved in the control of 

 garget and have been useful in determining the normal condition of 

 milk. It has been shown that the number of cells present in the 

 milk of apparently normal cows is much larger than has been 

 generally supposed, an average of 868,000 cells per cubic centimeter 

 having been found in the milk of 122 supposedly normal cows. 

 Only 59 of these cows gave milk containing less than 500,000 cells 

 per cubic centimenter, the number which has been frequently used 

 as the border line between normal and abnormal milk. Wide 

 fluctuations in numbers occurred both in the milk of the same cow 

 from day to day and in the milk of the various quarters of the same 

 udder. The number of cells in the strippings was invariably higher 

 than that in the milk from the major portion of the milking. A study 

 of the number of cells in the milk and of the bacteria in the udder 



