Anatomical Changes, Symptoms. 397 



joints and their surroundings, further gelatinous infiltration 

 of the subcutaneous connective tissue in the dewlap, on the 

 chest, and sometimes also on other parts of the body. 



Symptoms. The period of incubation, after subcutaneous 

 injection of the virus, in this disease is 6 to 27 days, after in- 

 halation 12 to 16 days (Nocard & Roux), and it is probably 

 not much longer under natural conditions. The reports of a 

 very long time of incubation may probably be traced to the fact 

 that the disease may be obscured for a time even after the initial 

 rise of temperature, and symptoms of lung affection are only 

 later perceptible. 



As the first symptom of the affection a rise in temperature 

 of % to 1 degree is observed^ which may become even higher 

 during the following days. 



The accurate observation of the body temperatuj-e in suspected 

 cases is of special importance. According to Lydtin, Fleming and 

 Brown animals in which the temperature is over 39.5°, and according 

 to Dele those in which it goes to over 40°, may be suspected of the disease 

 even if they fail to manifest other abnormalities. 



Simultaneously with the rise in temperature the animals 

 manifest more or less pronounced symptoms of general illness, 

 depending on the more acute or more chronic character of the 

 disease (debility, capricious appetite, delayed rumination, 

 diminished milk secretion, etc. ; according to Berndt, an edema 

 of the region of the throat appears at the beginning of the affec- 

 tion, which however soon disappears again). Almost at the 

 same time there is a short dry painful cough, which appears 

 especially in the morning after the animals rise at the opening 

 of the stable door, or on leaving the stable, and while drinking. 

 This may also be brought on by percussion of the thoracic wall. 

 Later the cough becomes more frequent, although without reso- 

 nance, moist and painful. In some animals there occurs a mod- 

 erate muco-purulent nasal discharge. 



This still indefinite clinical picture changes only slightly 

 for a time^ -gradually however symptoms of difficult respiration 

 become more emphatic. About 2 to 4 weeks after the appear- 

 ance of the first symptoms the respiration becomes accelerated 

 (30 to 40 per minute) and labored; the stronger extension of 

 the thoracic wall is followed mostly by double contraction of the 

 abdominal muscles, with a simultaneous trembling of the rump. 

 During inspiraition the intercostal spaces sink in, the nostrils 

 are opened wide, while the expiration is carried out with 

 grunting (later the respiration may become superficial and very 

 much accelerated). At the same time the animals turn their 

 elbows outward, they utilize the accessory muscles of respira- 

 tion, and also show the want of air by an anxious expression. 

 On pressure on the vertebral column this is bent laterally. 



Percussion reveals, in accordance with the extension of the 

 pneumonia, on one or both sides, behind the shoulder blade 



