630 THE PEOPLE'S FARM AND STOCK CYCLOPEDIA. 



laries and nerves of the skin, and causes the former to contract, 

 and the skin loses its power of depuration, or carrying off im- 

 purities arising from exhausted air, and tissues relax in the proc- 

 esses of assimilation and exhalation, and the blood, unpurified, 

 is driven to the lungs and membranes of the air passages. The 

 blood is abnormally charged with waste materials, and the or- 

 gans on which the work of the skin is thus thrown become 

 inflamed and congested, and disease follows. 



The history of nations has shown that the dry atmosphere is 

 unfavorable to the spread of contagious diseases, while the moist 

 or hot and damp atmosphere is most favorable. This may arise 

 from two causes. First, the evaporation from the skin is imper- 

 fect, the textures of the animal less elastic, and as a conse- 

 quence the circulation is languid. Second, the hot, damp at- 

 mosphere favors the rapid development of fungi of a para- 

 sitic nature, whose hurtful germs are rapidly and indefinitely 

 multiplied. 



Ventilation. From this we see some of the reasons why 

 pure air, and protection against the extremes of heat and cold 

 and moisture, are desirable. Of course, man can not control these 

 in nature. They are variable with the latitude and elevation 

 and characteristics of the country. Man can never make the 

 deltas of the Nile and the Mississippi as healthful regions as 

 are the elevated plains where the rivers have their origin. We 

 can, however, in the artificial arrangements of dwellings, stables 

 and sheds, see that the air is not vitiated, and its purity not 

 impaired. 



DRYNESS of the atmosphere of the dwelling or stable is of 

 the first importance. The horse has ever produced his highest 

 type in a dry elevated region, where there was a pure, dry brac- 

 ing atmosphere. The animals, of greatest activity dwell in dry 

 and elevated regions. The sluggish animals like the hippopo- 

 tami and pachyderms, flourish in the low marsh districts. The 

 nature of the horse demands first of all a dry place to sleep 

 and feed in. The damp stable favors development of fungi, 

 decomposition of litter, dung, and urine, and waste of feed, all 

 rich in nitrogeneous matter, which decays readily and defiles the 



