DISEASES OF SWINE AND OTHER ANIMALS. 145 



may be the cause of the disease obtaiuing access to the drove. We will 

 consider each cause aud how it cau be avoided. One of the coniiuou 

 causes of disease amoug s"syine is couhuement iu a peu where the air 

 does not circulate freely enough to carry off the carbonic acid expelled by 

 the hog. The result is that Irom dark to daylight the hogs are forced to 

 breathe an impure atmosphere. ]Mauy farmers build luximous pens, tight 

 and warm, and with an abundant ventilation only above, and abundance 

 of straw beloAV, forgetting that in such a house there is no ventilation, 

 that, in fact, the breath, loaded with exhalation fi'om the hog, is heavier 

 than the air aud sinks to the bottom of the i)en. Even if, by reason of 

 increased heat, the expired an- attempts to rise, the cold air from above 

 congeals the moisture and it falls as minute rain or snow. Other farm- 

 ers biuld tight pens without any thought of ventilation and let the hogs 

 pack in as they choose. In this case the air becomes very foid before 

 morning Tvith noxious gases, and if the owner would but put his hand 

 within he would hardly hnd the air with suihcient power to sustain life. 

 Now, it follows that we must have the pens so constructed that the swine 

 can have iJirre au", at the same time the intense cold of our northern 

 winters must be avoided, and either artilicial heat must be provided or 

 the heat of the hog utilized to increase the temperature where the sui*- 

 rounding atmosphere is below zero. We must remember that the uat- 

 ui-al haunts of the species in a wild state are in the torrid zone, and that 

 swine are never found in a northern climate in a wild state except where 

 they have escaped from domestication and become wild — that they are 

 not provided with fur to protect them from extreme cold. Xow, com- 

 mon sense teaches that when attempting to domesticate any Avild ani- 

 mal his natiu-al habits — food, climate, and mode of life — should be care- 

 fully studied. Again, effort has been made by careful breeding and feed 

 to change the natural form and development of the hog — to raise a breed 

 of swine with small bone, little muscle, and capacity for taking on fat 

 while young, and these changes have been made at the expense of nat- 

 ural strength and endurance. It is a common remark among farmers 

 that wild hogs do not have cholera, and acting upon this idea many 

 farmers keep their hogs in large timber lots without shelter, and are dis- 

 appointed to liud disease appear and carry off" a large proportion of the 

 drove. In these cases, where the hog is not confined and forced to 

 breathe foul air, but is exposed to the "sicissitudes of weather, with loss 

 of vital force by so-called imjirovement of breed, he becomes weakened 

 and succumbs. I have noticed this particularly in regard to diphtheria ; 

 several large droves were almost swept away in a few days, although 

 they had large range, i)ure water, and good food. This is true of diph- 

 theria poison, but I have never known the other fevers to attack any iso- 

 lated drove having pure air, clay soil iu range, and good food, unless hogs 

 having the disease were allowed in the same lot. The continement of 

 swine in close pens has another danger. The animal, heated by the con- 

 fined atmosphere aud damp straw bed, goes out at feed-call on a cold or 

 rainy morning with its skin and hair dam]) from the accumulation of the 

 gases which have congealed during the night. The cold, frosty' air is a 

 sudden change from the heated atmosphere of tlie pen, and bronchial 

 lung irritation is the result. It is also wet, and this moisture, if it is a 

 very cold day, is congealed, and the skin is chilled ; aud tluis, from this 

 error iu care, the animal is exposed to a double danger. To avoid these 

 dangers the pen should be so constructed tliat free ventilation can take 

 place at the top, as it is absolutely necessary in a cold climate to utilize 

 the natural heat of the hog to keep the pen at a moderate temperature. 

 It will not do in winter to have any openings below to admit cold air, 

 10 sw 



