EXAMINATION OP A SICK HOESE. 13 



THE SKIN AND THE VISIBLE MUCOUS MEMBHANES. 



The condition of the skin is a fair index to the condition of the 

 animal. The effect of disease and emaciation upon the pliability of 

 the skin have been referred to above. There is no part of the body- 

 that loses its elasticity and tone as a result of disease sooner than the 

 skin. The practical herdsman or flockmaster can gain a great deal of 

 information as to the condition of an animal merely by grasping the 

 coat and looking at and feeling the skin. Similarly, the condition of 

 the animal is shown to a certain extent by the appearance of the 

 mucous membranes. For example, when the horse is anemic as a 

 result of disease or of inappropriate food the mucous membranes 

 become pale. This change in the mucous membranes can be seen most 

 readily in the lining of the eyelids and in the lining of the nostril. 

 For convenience of examination the eyelids can readily be everted. 

 Paleness means weak circulation or poor blood. Increased redness 

 occurs physiologically in painful conditions, excitement, and follow- 

 ing severe exertion. Under such conditions the increase of circula- 

 tion is transitory. In fevers there is an increased redness in. the 

 mucous membrane, and this continues so long as the fever lasts. In 

 some diseases red spots or streaks form in the mucous membrane. 

 This usually indicates an infectious disease of considerable severity, 

 and occurs in blood poisoning, purpura hemorrhagica, hemorrhagic 

 septicemia, and in urticaria. When the liver is deranged and does 

 not operate, or when the red-blood corpuscles are broken down, as 

 in serious cases of influenza, there is a yellowish discoloration of the 

 mucous membrane. The mucous membranes become bluish or blue 

 when the blood is imperfectly oxidized and contains an excess of 

 carbon dioxide. This condition exists in any serious disease of the 

 respiratory tract, as pneumonia, and in heart failure. 



The temperature of the skin varies with the temperature of the 

 body. If there is fever the temperature of the skin is likely to be 

 increased. Sometimes, however, as a result of poor circulation and 

 irregular distribution of the blood, the body may be warmer than 

 normal, while the extremities (the legs and ears) may be cold. 

 Where the general surface of the body becomes cold it is evident that 

 the small blood vessels in the skin have contracted and are keeping 

 the blood away, as during a chill, or that the heart is weak and is 

 unable to pump the blood to the surface, and that the animal is on the 

 verge of collapse. 



The skin is moist, to a certain degree, at all times in a healthy horse. 

 This moisture is not in the form of a perceptible sweat, but it is 

 enough to keep the skin pliable and to cause the hair to have a soft, 

 healthy feel. In some chronic diseased conditions and in fever, the 

 skin becomes dry. In this case the hair has a harsh feel that is quite 

 different from the condition observed in health, and from the fact of 

 Digitized by Microsoft® 



