98 CLINICAL DIAGNOSTICS. 



matory conditions occasioning either irritation or depression 

 of this organ can bring about marked change in the rhythm 

 of respiration. The value of these changes to diagnostics is 

 limited. 



A peculiar change in the rhythm and intensity of the respi- 

 rations, occurring in cycles, is noted in severe intoxications 

 and infections. It is known as Cheyne-Stokes respirations. 

 Following a pause in the respirations the breathing progres- 

 sively increases in frequency and intensity to dyspnea. It then 

 slowly subsides until another pause when the cycle is repeated. 



2. The intensity (depth) of the respirations is not marked 

 in healthy animals standing at rest. The alae of the nostrils 

 are hardly moved, and the ribs but slightly raised. The i n- 

 tensityis increased by exercise ; if it is augmented 

 and the animal at rest, it denotes disease. The horses dilate the 

 nostrils trumpet-like, dogs open the mouth (pant) and pro- 

 trude the tongue. The movements of the ribs and flanks are 

 pronounced. The development of the intensity agrees with 

 the degree of dyspnea. 



The intensity is diminished when the pleura, chest wall 

 or diaphragm is diseased and painful. 



The intensity can become asymmetrical in 

 that one side of the thorax undergoes a deeper or more rapid 

 movement than the other side. This is seen in painful uni- 

 lateral pneumonias or pleurites. 



3. When the rhythm and intensity of breathing is normal 

 and the ribs and abdomen are moved with even regularity, the 

 type of the respirations is spoken of as costo-abdominal. 

 if the respiratory movements are produced principally by the 

 auxiliary muscles of breathing, which dilate the thorax, the 

 type becomes costal. The costal type is seen to occur where 

 air can not pass freely into the thorax or where the diaphragm 

 or adjacent organs are diseased. (Abdominal tumors, ascites, 

 tympanitis.) 



When of the costal type the respirations are slow. 



