640 THE PEOPLE'S FARM AND STOCK CYCLOPEDIA 



is changed in color, the oxygen acting on the carbon forms car- 

 bonic acid, which is an impurity, and is thrown oil' by expira- 

 tion into the atmosphere around us. The atmosphere that was 

 inhaled contained oxygen and nitrogen. In that combination 

 they are beneficial. As soon, however, as the oxygen has been 

 acted on by the blood or lungs, nature throws off the nitrogen 

 with the carbonic acid. Now, as nitrogen, in some forms, and 

 carbonic acid are injurious to animal life, it will be seen how 

 imperative is the demand that these do not again enter the 

 lungs; but if the ventilation is defective, and fresh, new air is 

 not furnished, the inhalation of the second-hand or oft-used air 

 goes on to the inevitable contamination of the blood. We get a 

 better idea of the amount of carbonic acid thrown off from the 

 lungs by noting that Carpenter gives the average amount per 

 hour set free by a full-grown man to be about one hundred 

 and sixty grains, or in twenty-four hours about 3,840 grains, or 

 eight ounces Troy weight. 



"Warm Stables. As external cold increases the amount 

 of carbon thrown off, we have an incentive to keep our stables 

 warm in the winter. But in this we encounter another danger. 

 The effect of several horses and cattle shut up in a close stable 

 can be imagined. The air becomes laden with the excreted car- 

 bonic acid, and with the impurities added by the urine, dung, 

 and decomposition of vegetable matter, increased by bad drain- 

 age, we have a' stifling atmosphere. 



It is not surprising that in the neglected stables we find sore 

 throat, inflamed lungs, diseased eyes, grease or scratches, farcy, 

 mange, and even glanders. Nor is it wonderful that when 

 disease appears it spreads rapidly through the whole herd or 

 stud, since they have all been exposed to the same kind of pro- 

 voking causes. The heat of the stable sets free the nitrogen 

 and hydrogen abounding in the vegetable matter, and in the 

 dung and urine, and these gases unite and form ammonia, the 

 salts of which were first made from camels' dung, in the district 

 of Ammonia, in Africa. Hence the name. The ammonia is a 

 pungent gas, and acts powerfully on the eyes and nose and 

 lungs. Since any affection of the wind and sight of the horse 



