74 Veterinary Medicine. 



acquired and the novel conditions of life cease to be injurious. 

 That this varied power of resistance is not confined to the higher 

 animals would appear from the experiments of W. Edwards on 

 cold blooded animals. He subjected them in winter and in sum- 

 mer respectively to a very low temperature and found that 

 whereas in summer their temperature declined 3° to 6° Cent., in 

 winter they had a greater resistance and barely declined TTF^hs of 

 a degree. 



The action of cold on the surface of the body often leads to 

 morbid states of the air passages as the result of nervous sympa- 

 thy. A beast is subjected to a keen cold wind, is attacked with 

 shivering, and inflammation of the chest supervenes. The result 

 is rendered more certain if the wind is associated with rain and 

 if the animal has been previously in a state of perspiration. A 

 heavy coat of hair, a profuse perspiration, and a cold draught 

 often combine effectively to produce respiratory disease. 



It must be added that the chilling debilitates the nuclei of the 

 animal tissues, and lessens their power of resistance to noxious 

 influences. The excess of cold in the freezing of a part, is fol- 

 lowed by congestion and even violent inflammation with perhaps 

 sloughing after it has been thawed. The persistence of such 

 tissue debility is familiar to us all in the example of chilblains. 

 A less extreme application of cold affects the tissues and nuclei 

 less powerfully, but none the less surely. The increased liability 

 to disease of the chilled system is strikingly illustrated in the ex- 

 periment of Pasteur with anthrax. The chicken which had 

 proved refractory to an ordinary dose of anthrax virus, was 

 dipped in water at ordinary temperature until the heat of its body 

 was reduced, and then it fell an easy victim to the anthrax 

 bacillus. In the same way the person who recklessly exposes 

 himself to wet and chill falls a ready victim to intermittent or 

 yellow fever from which he would otherwise have escaped. De- 

 bility from another cause, such as bruise or laceration, favors 

 deep-seated invasion by pus cocci, and a resulting abscess, from 

 which the patient would have remained free, but for such 

 traumatism. 



But the effect of cold is not confined to the sympathy between 

 the skin and respiratory mucous membrane, nor the revulsion of 

 the blood toward internal organs, nor to the debilitating of the 



