10. There should be good light, good ventilation, and good drainage in the cow-house.
11. The cow-house should always be kept clean.
12. Feeding and bedding, unless moist, should be done after milking.
13. A dustless milking-room is desirable.
14. Milk should not stand in the cow-house.
15. If milk is aërated, it should be done before cooling and in pure air.
16. The sooner the milk is cooled after milking the better.
17. Keep the milk as cold as possible when once cooled.[45]
The supply of milk is conducted, to a large extent, by towns' dairies, which depend for their supplies upon the dairy farm in the country, and it is obvious that a certain period of time must elapse, in the generality of cases, before a town's dairy receives its supply in the ordinary course, and this constitutes the greatest difficulty in modern dairy practice, owing to the liability of the milk to absorb bacteria, which during transit may multiply enormously.
The multiplying of bacteria in milk at different temperatures is easily demonstrated, and the result of this has been stated in various forms many times over. As a graphic means, however, of showing the increase that takes place in the numbers of germs present, and the consequent product of acidity, the table below by Conn may be given.