NONCONTAGIOUS DISEASES OF THE ORGANS 

 OE RESPIRATION. 



By William Herbert 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 infre- 

 quently do we find that the successful veterinary practitioner 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 func- 

 tions of the organs in health, but to adopt a rigid system of details of 

 examination, without which successful results 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 animals 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. 



