H0V8IN0 AND HYGIENE 265 



The need of ventilation is further emphasized by King,' 

 who quotes Cahn as giving the cubic feet of air breathed by 

 certain animals per thousand pounds of live weight as follows : 



Cow ... . . 2804 



Horse . . 3401 



Hen . 8278 



Pearl and Surface^ have to say, in reference to certain 

 breeding experiments: " Conditions of housing have a marked 

 and definite influence on the mean or average fertility and 

 hatching quality of eggs." In the experiments discussed 

 it was found that both fertility and the hatching quality 

 of eggs were very much better when the breeding was done 

 in a curtain-front house, which furnished an abundance of 

 fresh, pure air, than when it was done in what was formerly 

 considered to be a highly desirable type of heated house with- 

 out curtain front, but with a supposedly adequate system of 

 indirect ventilation. 



Ventilation and Drafts. — ^It is difficult to so house fowls that 

 they will have as full advantage of fresh air as they have in 

 the tree and at the same time be protected from drafts. 

 While a fowl can roost all night in a tree when it is blowing 

 a gale and not take cold or suffer any other noticeable ill 

 effects, it will take cold very quickly if compelled to be in a 

 draft inside of a house. A nail-hole improperly located beside 

 the perch will be the cause of colds that form the beginning 

 of epidemics of roup, diphtheria, catarrh, or other kindred ills. 

 While ventilation should be ample it must be without drafts. 



Artificial Warmth versus Fresh Air. — ^A moderate tempera- 

 ture is one of the conditions of spring which is conducive 

 to high production. The question arises whether it will be 

 profitable in the broad sense to furnish artificial heat even 

 at the expense of ventilation. There is not nearly as much 

 evidence on this point as there should be, but such as we 

 have seems to point decidedly to the conclusion that to have 

 air fresh is of far greater importance than to have it warm. 



' Physics of Agriculture. ' Maine Bulletin No. 168. 



