THE SANITARY CONDITION OF MILK 79 



quality of cheese was due to the milk obtained from 

 one herd. Whenever the milk from this herd was 

 omitted, good cheese was produced, and when the 

 milk was added, a poor quality was obtained. An 

 examination of the surroundings of the herd which 

 caused the trouble showed that the cows in passing 

 to and from the milking shed walked through a 

 marshy place covered with green pond scum and 

 other decomposing materials, particles of which ad- 

 hered to the udders, dried, and then fell into the 

 milk pails during milking, and fouled the milk. In 

 the care of animals, the importance of an abundance 

 of sunlight cannot be overestimated. Many disease 

 germs are destroyed by the action of strong sunlight. 

 Strong sunlight and pure air are the best disinfec- 

 tants, and in many stables there is a great lack of 

 both. Experiments made with growing animals show 

 that there is a decided difference in general health 

 and vigor between those reared in dark and light 

 stables. When the stable is not properly ventilated, 

 the carbon dioxid thrown off by the lungs as respira- 

 tion products unites with the ammonia formed by the 

 decay of the manure and produces ammonium car- 

 bonate, which is often deposited in the form of a 

 white coating upon the stones and beams of the 

 stable. This shows that the stable is poorly venti- 

 lated. Ammonium carbonate is an irritating alka- 

 line compound, and when present in excessive amounts 

 has a destructive action upon mucous membranes. 

 It is this material which collects upon carriage tops 



