152 Milk and Its Products 
ern methods of waterproofing the stable floors have 
overcome quite largely the objections that were for- 
merly made to cement because it was damp, and con- 
sequently a great conductor of heat. 
It is important that the stables be constructed with 
particular reference to ventilation. It is essential that 
the air in the stable shall be comparatively fresh at 
all times. While there is no accepted standard or 
easy means of determining the purity of the air in 
the stable, yet it may be said that it will be sufficiently 
pure when, on entering the stable from out-of-doors, 
the air presents a fair degree of freshness, with no 
marked animal odors or perceptible staleness. If such 
odor or staleness is obvious, the stable should be 
considered not sufficiently well ventilated. 
As dust is a great carrier of bacteria, it is impor- 
tant to admit only pure air and to have all dairy-rooms 
and stables as free from dust as possible. When con- 
ditions will permit, it will be found an advantage to 
have as much as possible of the grounds surrounding 
the stable covered with turf. This will prevent, to a 
considerable degree, the entrance of dust in the sta- 
ble, particularly during the dry summer months when 
it is most difficult to produce milk having a low 
bacterial content. 
Sanitary stables.—It is important that sunlight be 
permitted to enter the stables. This feature is con- 
sidered of so much importance by some milk producers 
that they endeavor to arrange their stables so that 
the sunlight may be permitted to enter on one side of 
the stable in the forenoon and on the other side in 
