OF VETERINARY MEDICINE. "' 171 



produce the disease, but cohabitation of the diseased and healthy 

 animals seems to transmit the infection. It cannot really be ex- 

 plained how the infection is carried. It may be from the pus or 

 it may be from the expired air or discharges of the diseased 

 animal. 



Etiology. — The streptococcus equi is the cause. The period 

 of incubation is from one to two weeks. 



Scmeiology. — There is at first a high fever which is soon fol- 

 lowed by loss of appetite and swellings around the throat and 

 branches of the lower jaw. The abscesses may be numerous or 

 few, large or small. Regularly they occur around the head and 

 throat. If the retropharyngeal glands are involved the dyspnoea 

 may be dangerous and death from asphyxiation occur. The 

 mortality is not high. About 99 out of a 100 recover, but occa- 

 sionally one will die. The death depends a great deal upon the 

 environment and the weather. Wet and cold are unfavorable to 

 the sick animal. 



Strangles usually starts with fever and a discharge from th? 

 nose, and there may be some cough. At first the pulse is rapid 

 and in a few days it becomes w^eak. The mucous membranes 

 become injected, and if the abscesses occur around the throat 

 and maxillary glands, the deglutition is apt to be interfered with. 

 In a few days they will rupture spontaneously unless they are 

 too deep-seated. Then the fever subsides, the appetite returns 

 and rapid recovery takes place. The temperature may start out 

 at 106 but in 4 days go down to 104, at which place it stays until 

 the abscess ruptures, when it returns, to normal. 



In the irregular form the character of the fever is the same 

 but the abscesses form somewhere else than around the throat, 

 eithe. internally or externally. They are often seen in the liver, 

 spleen and lymph glands and the pectoral and inguinal branches 

 of the lymphatic ducts. They may break out about the legs. If 

 the abscesses are superficial and can be opened or ruptured the 

 animal will make a good recovery, but if the abscesses follow one 

 another then the animal may not get well for six or eight months. 

 If they rupture internally the case may be fatal. The pericardium 

 and occasionally the heart itself is often the site of these ab- 



