SOURCES OF INFECTION IN THE STABLE. 31 



and free spores were found on the contaminating particles 

 in milk fresh from the cow, while such ones did not appear 

 to any appreciable extent in the milk itself. After some 

 time the impurities showed a far smaller number of bac- 

 teria than before, while the milk itself teemed with them; 

 the milk may therefore be infected even from the impuri- 

 ties introduced in the same. 



At the same time as I made these observations I found 

 micro-organisms and spores outside of the milk of exactly 

 the same kinds as those found on the impurities of the 

 milk, viz., in the manure remnants which had had a chance 

 to remain for a time in the warm and moist atmosphere of 

 the stable, and thereby became the seat of a luxuriant bac- 

 terial growth, and also in the dirt on the skin of the cows, 

 where the bacteria may develop rapidly, greatly benefited 

 by the animal heat and moisture. 



Impurities in the Milk. As the impurities which get 

 into the milk even during the milking itself play such an 

 important part in the infection of bacteria, it is important 

 to learn their origin. The microscopic examination gives 

 a good indication of their origin. I have found the fol- 

 lowing kinds of impurities in unstrained milk fresh from 

 the cow : 



1. Manure-particles (numerous). 



2. Fodder-particles (which have not passed the aliment- 

 ary canal of the animals). 



3. Molds and other fungi. 



4. Cow-hair (numerous). 



5. Particles of the skin. 



6. Human hair. 



7. Parts of insects. ^^x^/$>/ 



8. Down from birds. 



