170 CLINICAL BACTERIOLOGY AND 



and tracheal mucosae follows; and the first indication to 

 the ordinary observer of anything being amiss is a short, 

 dry, strong, and intermittent cough. The animal at this 

 stage may look well, feed well, and give, if a milch cow, 

 the usual quantity of milk ; in fact, we have even noticed 

 an increased supply of milk at this stage, probably due 

 to an increase of opsonins thrown into the blood-stream. 

 As time goes on the cough becomes more pronounced, is 

 more persistent, and not so dry; and also there is an 

 expectorate, but, as this is usually swallowed, it is difficult 

 to detect. One can, if standing on the left side of the 

 patient, however, often see it pass along the gullet as a 

 bolus after a fit of coughing. 



There may also be signs of pain caused by the act of 

 coughing, as evidenced by rigidity of the costal muscles 

 and the emission perhaps of a grunt. The animal now 

 begins to lose in condition. The appetite may be good, 

 and yet the patient does not seem to thrive as she did 

 formerly, or the appetite may be bad, with resultant falling 

 away of flesh. The respiratory sounds may, and usually 

 do, reveal a variety of conditions. Vesicular murmurs may 

 be either increased or diminished, or even absent. Prom- 

 inent bronchial blowing sounds may be noticed. There 

 may also be pronounced crepitus over the whole pulmonary 

 area. There are very decided dry or moist rales, which 

 are materially increased on exercise. In pulmonary cases 

 of some standing, digestion becomes impaired, this doubt- 

 less being due to the process of auto-intoxication primarily 

 depressing the vagus and leading to general malnutrition, etc. 

 Fermentative changes now go on in the alimentary canal, 

 as evidenced by eructation of gas and foul-smelling fasces. 

 If the mediastinal and prebronchial lymphatic glands are 

 enlarged and diseased — and they usually are — pressure 

 on the oesophagus takes place, rumination is interfered 

 with, and eructation of gas from the rumen is a prom- 

 inent symptom. When one sees this symptom promin- 

 ently in a milch cow with an intermittent and troublesome 



