804 BOVINE PATHOLOGY. 



is left standing in a current of air, and is otherwise 

 exposed. The working ox is somewhat similarly treated, 

 and hence of all bovines is most liable to diseases of respira- 

 tory organs, but he is not by any means pampered, and 

 seldom overworked. Cattle, especially when fat, are 

 sometimes overdriven, but ordinarily are in a state of 

 quietude in the stalls of not overdosed shippons or in 

 pastures. Under these circumstances traumatic causes 

 are the main influences which generate diseases of the 

 breathing apparatus. Dairy cows and prize fattening beasts 

 are certainly continuously subjected to the close and foul 

 atmosphere of byres, but they are not exercised and do 

 not change from heat to cold, so the predisposition engen- 

 dered by ammoniacal fumes and constant inspiration of 

 warm air laden with impurities seldom receives the 

 exciting cause necessary to give rise to acute pulmonary 

 disorder. The effect is more marked in arousing heredi- 

 tary or acquired tendency to scrofulous disease, especially 

 phthisis. We have previously made some general remarks 

 on the nature of respiratory processes, but must now recall 

 to our minds certain special means of diagnosis, which 

 acquire particular importance in relation to the diseases 

 under consideration. 



Auscultation depends on the motion of air through 

 the air-passages, and the movements of the chest and 

 other parts during breathing. It is termed immediate 

 if the ear is applied directly to the surface, mediate 

 if the acoustic connection is indirect. The former method 

 is open to the objection that the surface is often 

 not fit for contact, as when the animal is covered with 

 lice. It is most useful as avoiding extra friction sounds, 

 which result from the intervention of a foreign body 

 between the ear and the chest. Generally a handker- 

 chief is placed on the surface, and a little practice enables 

 the observer to automatically ignore any complications 

 due to its presence. The stethoscope is a long tube with 

 a trumpet-shaped extremity for even contact with the 

 surface, and an ear-piece ; it is seldom used in veterinary 

 practice. It is an artificial prolongment of the external 



