296 BUILDINGS, SANITATION, AND DISEASES 



walls are constructed and is not likely to prove at all injurious 

 to the pigs. 



A very good wall can be made by setting two-by-four 

 scantlings on end ; and first boarding inside and out with, rough 

 lumber. This rough lumber should then be covered with tarred 

 paper, and then the walls should be tightly boarded up with 

 matched lumber. If preferred, the outside of the pen may be 

 clapboarded. Smooth, matched lumber is best for the inside 

 of the pen. Patent building paper may be used outside. 



If it is thought desirable to have a loft over the pen, the 

 ceiling can be made of poles, placed a few inches apart, and 

 well covered with straw. The straw absorbs moisture and helps 

 to keep the pen dry. Where this is done, the straw should be 

 renewed at least every year, otherwise it becomes a harbor for 

 dust and disease germs. 



Ventilation. Thorough ventilation is a great help in pre- 

 serving dryness, but it is a difficult thing to secure in a piggery 

 without unduly lowering the temperature. It is an aid to 

 ventilation to provide a large air space; in other words, to 

 have a high ceiling. The tendency at present is to do away 

 with the common loft over the piggery, and to have the space 

 above the pigs extend to the roof. This gives more air space 

 and makes ventilation a simpler problem, but it necessitates 

 lining the under side of the rafters with matched lumber in 

 order to prevent the pen from becoming too cold. 



Shaft Ventilators. The admission of fresh air can be 

 provided for by constructing 'shafts in the walls at intervals 

 of fifteen or twenty feet. These shafts should not be more 

 than about four by six inches in size, and should open outside 

 near the ground, and inside at the ceiling. Provision should 

 be made for closing, or partial closing, of these intakes Avhen 

 cold air is admitted too rapidly. The outlets may consist of 



