Symptoms. 549 



Symptoms. In keeping with the extraordinary variability 

 of the pathologic-anatomical changes that occur in tuberculosis, 

 the symptoms of the disease vary not only in different species 

 of animals but to an almost equal extent in individuals of the 

 same species. The insidious and long drawn out course of the 

 disease gives rise to additional variations. 



In advanced stages of the disease the body temperature is 

 at times temporarily elevated. The course of the fever is in- 

 termittent or remittent, with evening exacerbations and morn- 

 ing remissions; sometimes the typus inversus is observed. In 

 the chronic course of the disease febrile attacks lasting several 

 weeks alternate with free intervals of the same duration. Near 

 the termination of the disease the fever is usually high and 

 continuous. The same is observed when an acute miliary tuber- 

 culosis develops from a chronic affection. 



Tuberculosis of Cattle. The period of incubation, after 

 severe artificial infection, is rarely longer than two weeks. In 

 natural infection it is much longer; sometimes months and 

 even years may elapse before the appearance of the slightest 

 indications of disease become manifest to ordinary observation. 



According to Nocard and Eossignol artificial infection by inhalation requires 

 19 to 32 days and alimentary infection 32 to 48 days before the animal will react 

 to tuberculin. In experiments conducted with calves by the authors symptoms of 

 fever appeared eight days after the intravenous injection of 0.02 gm. of cultures 

 of tubercle bacilli. 



Pulmonary tuberculosis, the most frequent form of the dis- 

 ease, manifests itself by a short, dry, vigorous cough. At first 

 this occurs only when cold or dusty air is inhaled or when the 

 circulation is accelerated by the sudden rising of the animal 

 or by drinking cold water. In this stage the appetite is usually 

 good but symptoms of exhaustion may be observed after pro- 

 longed exercise. 



Gradually, usually after the lapse of months, symptoms 

 pointing to pulmonary affection become more pronounced. The 

 cough becomes more frequent and painful, may be dry and coarse 

 or feeble and almost soundless. From time to time the animals 

 discharge a ropy, muco-purulent, yellowish-gray secretion from 

 the open mouth ; as a rule however this secretion is swallowed 

 as may be demonstrated by observing the left esophageal grove 

 immediately after an act of coughing. It may also be retained 

 in the space anterior to the soft palate between the tongue and 

 last molar teeth where it may be reached by the hand (Ostertag). 

 Sometimes the bronchial secretion is discharged through the 

 nose; in this case the presence of pus corpuscles, alveolar 

 epithelium that has undergone fatty degeneration, fat crystals, 

 elastic fibres and tubercle bacilli may be demonstrated. 



As the cough increases in frequency the type of respiration 

 begins to change; it becomes more frequent and laborious, in- 

 spiration assumes more of a costal type and expiration, which 



