44G SYMPTOMS OF DISEASE OF RESPIRATORY ORGANS. 



poisoning ; and whether or not the supply of rcspiraLle air is 

 sufficient for the animal's wants. 



Should these efforts at breathing, which ought always to 

 be regarded as a compensatory action, not speedily restore the 

 proper relation Avhich ought to subsist between the amounts of 

 oxygen and carbonic acid in the blood, we know that other symp- 

 toms, and a somewhat different condition, is certain to follow. 

 Certain parts of the nervous centres become functionally inert, 

 and a train of symptoms, comprising various nervous phenomena 

 and blood-changes, recognised as asphyxia, is apt to destroy life. 



4. "Whistling and Eoaring. — These, although probably in the 

 large majority of instances truly larjmgeal sounds, and appear- 

 ing in connection with acute diseases of the air-passages, or 

 indicative of some impediment to the proper performance of 

 the respiratory act, are, from their frequency of occurrence and 

 the importance of their recognition in relation to the question 

 of soundness, deserving of particular attention. 



Under the general term of 'roaring,' we are inclined to group 

 all those abnormal sounds emitted by horses under exer- 

 tion, and known as ' roaring ' or ' whistling ;' not because we 

 regard them as in every case but modifications as to severity 

 or intensity of one and the same sound, but merely because 

 they are all deviations in the matter of sound from the con- 

 dition of normal respiration. In investigating this symptom 

 of abnormal sound, amongst several other questions, attention 

 is particularly required to be directed to the following : 



A. Whether it has appeared suddenly as the Sequel of some 

 Acute Disease ofanypaii of the Air Passages. — The fact of the 

 development of this abnormal sound occurring suddenly, and 

 succeeding some acute disease connected with the organs of 

 respiration, is favourable, rather than unfavourable. The defect 

 in such cases may arise from the partial organization or non- 

 removal of certain products of the previous inflammatory action. 

 These products may have been effused into the submucous tissue 

 of the laryngeal membranes, thus constricting the opening of 

 the larynx, and altering the pitch and tone of the sounds emitted 

 during respiration. Knowing the probabilities of the occur- 

 rence of this, defects in respiration succeeding catarrhal and 

 other analogous affections, the examination of horses at this 

 time ought to be cautiously proceeded with. 



