60 ■ ^ MOUNTED INSTRUCTION 



to clean up his feed, he usually has something- out of order about him 

 and should be carefully examined and watched. 



The early detection of indications of disease and the necessary 

 action promptly taken is of far greater importance than any treatment 

 that can be given once the disease has developed. Often the detection 

 and isolation of one animal sufifering from a communicable disease 

 means the saving of thousands of dollars in horse flesh and the pre- 

 vention of an animal shortage v^hich would have disastrous results. 



CAUSES AND PREVENTION OF DISEASE 



Definition: Li\ing germs constitute the specific and primary cause 

 of certain diseases and may be transmitted from one animal to another. 



Description: Bacteria are vegetable microorganisms. Each indi- 

 vidual consists of a sing'le cell. They are of almost infinite number of 

 species and varieties, and are present in the atmosphere in particles of 

 room dust, in drinking water, in the soil, and, in fact, almost every- 

 where in great abundance. 



Size: They are extremely small, recpiiring the highest powers of the 

 microscope to make them distinctly visible. It is estimated that mil- 

 lions mav live comfortablv in a single drop of fluid. An average bacil- 

 lus is from 1-25.000 to 2-25,000 of an inch long-. 



Nutrition: Hacteria use for their food compound formed from the 

 chemical elements, oxyg'en, nitrogen, carbon, hydrogen, phosphorus, 

 and sulphur. Like higher beings, thev vary in their likes and dislikes. 

 What is wholesome for one may be very injurious to another. Each 

 species has its certain conditions of moisture, temperature, and chemi- 

 cal reaction which are most favorable. 



How Scattered: Germs of diseases are scattered by a very great 

 many agencies. Germs are disseminated by means of diseased car- 

 casses, stock cars, and they may be easily transferred by the shoes or 

 clothing of persons who walk through an infected area. Dogs un- 

 doubtedly serve to scatter diseases over wide areas, and possibly birds. 

 It is possible also for the germs to be scattered by particles of dust and 

 litter in high winds. Watering troug^hs, tanks, ponds, and sluggish 

 streams are all common courses for spreading infectious diseases. 



Development of Outbreaks: It seems to be true of several and pos- 

 sibly so of a great many diseases, that the germs may be present 

 with the animal or his surroundings but not virulent enough to produce 

 disease. Under favorable conditions and perhaps after passing through 

 the bodies of several susceptible animals in succession they may in- 

 crease in virulence sufficiently to produce disease. 



Some of the germs producing diseases of domestic animals are be- 

 lieved to live for very long periods of time and even vegetate outside 

 the animal body, possibly upon or within the tissues of plants. Some 

 germs, especially in the resting or spore stage, may live for very long- 

 periods of time, and under very unfavorable conditions and retain 

 virulence. 



