26 
F. S. BILLINGS. 
tinued obstruction of the bronchioli, then the peripheral parts of 
the lobuli become atelectatic. The surface of the lungs then 
loses its smooth appearance. By pressing the lingers over the 
parts in question, we are able to feel the broncho-pneumonia cen¬ 
tra, as small noduli. Each nodulus shows on transverse section a 
yellow point (centrum) which corresponds to the point of entrance 
of the bronchiolus. 
Experience has taught us that post broncho-pneumonia atelec¬ 
tasis develops by animals which do not breathe sufficiently, that 
is, by poorly nourished and animals weakened by the processes of 
disease. The bronchiolitis and the alveolar catarrh give the mate¬ 
rial for the obstruction of the bronchioli, and the insufficient res¬ 
piration is the cause of the obstruction. The product given by 
a catarrh of the part of the lungs in question is movable, conse¬ 
quently capable of expectoration; but the insufficient respiration 
is the reason why the bronchioli and the alveolae around the same 
become filled. In this filling is to be sought the condition to the 
development of atelectasis. 
Atelectasis may also embrace greater sections of the lungs ; 
the above-given data are amply sufficient to explain the reason for 
the same. The diaphragma is the most important inspiration’s 
muscle. Meteorismus and ascites must therefore exert a disad¬ 
vantageous influence upon the respiration. These conditions force 
the diaphragma forwards, and therefore make the respiratory sur¬ 
face smaller and render the movement of the diaphragma diffi¬ 
cult. Experience has taught that either of the above, of them¬ 
selves, do not disturb the respiration to an excessive degree, but 
that dyspnoetic phenomena become apparent, when disturbances 
of the respiration were already present. I will not here give the 
reason for my assertion, but will only mention that I can prove 
their correctness on the dog. Dogs demonstrate scarcely any 
dyspnoea, by a frequently very extensive tympanitis, i. e. such 
which follows or accompanies peritonitis. 
But as soon as with the tympanitis, bronchitis is developed, they 
demonstrate very severe dyspnoetic phenomena, even when the 
bronchitis has only attained a small extension. In these cases the 
dyspnoea stands in no proportion to the grade and extension of 
