SANITARY MILK PRODUCTION 149 



sources. Cultures of the Bad. abortus type were isolated from 45, or 

 23.4 per cent., of the 192 samples of milk studied; the highest number 

 found per cubic centimeter was 50,000. 



From the study Evans concluded that there is a definite udder flora 

 comprising bacteria which belong to the parasitic type. She remarks 

 that it is not surprising to find the organisms of the same type as those 

 common on the skin and mucous membranes of man and animals. The 

 majority of the organisms on the skin are non-pathogenic but there are 

 some virulent forms and similarly the majority of those in the udder appear 

 to be harmless but organisms virulent to the lower animals were isolated. 

 While the pathogenic properties of the organisms from the udder are not 

 discussed in this paper as a whole the data presented constitute a valid 

 argument for the pasteurization of all milk. 



Besides harmless microbes, milk from the udder at times contains the 

 germs of disease. Cows with tuberculous udders secrete milk that con- 

 tains large numbers of tubercle bacilli that are infectious to both humans 

 and calves. Cows sick with anthrax yield milk containing anthrax 

 bacilli and the milk of cows with the trembles has often proved fatal to 

 those who have partaken of it. Barber's proof that a staphylococcus 

 isolated in the milk fresh from the udder of a cow was the cause of many 

 cases of gastro-enteritis shows that organisms that are not recognized as 

 disease germs may at times cause severe sickness. 



Fecal Contamination of Milk. The fecal and urinary discharges of 

 cows for the sake of decency should be kept out of milk; the very idea of 

 their presence is abhorrent. Both may be the cause of disease ; it is known 

 that they may transmit tuberculosis and other maladies, particularly the 

 intestinal disturbances of infants and less frequently of adults, are at- 

 tributed to the use of milk heavily polluted with animal excrement 

 though the specific exciting organisms may not be known. Of course 

 cows are constantly defecating and urinating and some of the matter 

 passed adheres to the coat and will fall into the milk unless cleanly 

 methods of milking are used. Bacteria of the B. coli-Bact. lactis aerogenes 

 group occur abundantly in feces. They are likely to form a gassy curd 

 and also to produce an offensive odor and a disagreeable taste in milk and 

 in cream soured by their action, consequently they impair milk for cheese 

 making and for the city milk trade and cream also for use in manufactur- 

 ing butter. So both to protect the public health and for strictly commer- 

 cial reasons everything should be done to check fecal contamination of 

 milk. 



Contamination of Milk by Discharges from the Nose and Mouth. 

 The nasal and buccal discharges of cattle are the source of bacterial con- 

 tamination of milk. St. lacticus, which is the cause of ordinary milk 

 souring, Esten has pointed out is always present in large numbers in the 

 cow's mouth, consequently in licking herself she transfers them to her 



