NONCONTAGIOUS DISEASES OF THE OEGANS 

 OF RESPIRATION. 



By William Hebbert Lowe, D. V. S. 

 [Revised in 1904 by the author.] 



In the determination of disease in the human being the physician is 

 aided by both subjective and objective symptoms in making his diag- 

 nosis; but the veterinary physician, in a very large majority of cases, 

 is obliged to rely almost solely upon objective symptoms, and perhaps 

 in no class of diseases is this more true than in the exploration of 

 those under consideration. This condition of affairs has a strong 

 tendency to develop observation and discernment in the veterinarian, 

 and not infrequently do we find that the successful veterinary prac- 

 titioner is a very accurate diagnostician. But in order to make a 

 differential diagnosis it is not only necessary to have a knowledge of 

 the structure and functions of the organs in health, but to adojit a 

 rigid system of details of examination, without which successful re- 

 sults can not be reached. 



History. — The history of a case should always be ascertained so far 

 as possible. The information obtained is sometimes unsatisfactory 

 and not to be depended upon, but even when such is the case it is 

 advisable to weigh the evidence from every point of view. 



In connection with the history of every case it is always of primary 

 importance to ascertain the cause of illness. A knowledge of the 

 origin and development of a disease is important, both in making 

 a diagnosis and in formulating the treatment. Exposure to cold and 

 dampness is frequently the exciting cause of affections of the organs 

 of respiration. 



The experienced practitioner is always sure to ascertain whether 

 the particular animal he is called on to attend is the only one in the 

 stable or on the premises that is similarly affected. If several ani- 

 mals are similarly affected, the disease may have a common cause, 

 which may or may not be of an infectious nature. 



Another thing that the experienced practitioner ascertains is what 

 previous treatment, if any, the animal has had. Medicine given in 

 excessive doses sometimes produces symptoms resembling those of 

 disease. 



