1889.] Etiological Classification of Diseases. 967 
There are many pulmonary complications of germ-parasitic 
origin of this invasio-non-infectious type, which occur in the 
lungs, which have not received the attention their merits de- 
serve. In diseases of a specific acute infectious character 
(exogenous in origin especially), such as typhus abdominalis, 
the true Swine-Plague, the corn-stalk disease, one of the chief 
phenomena is a very high fever, and the most essential lesions 
of such diseases are the extreme parenchymatous changes in 
the muscles, and dense glandular organs such as the liver and 
kidneys. Added to these, and of equal importance, are similar 
changes in the heart-muscles, and the disturbance of the secre- 
tive functions of the kidneys. Briefly speaking, the elements 
of these organs are swollen, their condition, as a whole, is 
more or less anaemic, due to the pressure of the swollen cells 
upon the delicate capillary ramifications. These pathological dis- 
turbances necessarily lead to pressure, a vis a frontis, upon the 
circulation towards the points of least resistance ; that is, to an 
accumulation of the blood in those organs the structure of which 
offers the best support to the blood-vessels, and thus favors their 
distention and engorgement. The two points are, first, the lungs, 
and next in importance the intestines. The lungs, however, 
chiefly deserve our attention. This condition of engorgement 
finds additional support in the weakened propelling power of the 
heart, due to the parenchymatous 'disturbance of the muscles. 
Again, the prostrate position of the individual [in man] in such 
cases, the inability, or non-desire for movement in both man and 
animals, increases this condition in the lungs, because the muscles 
are not called upon to take up any nutrition, and hence all con- 
ditions favoring diffusion of the blood are partially stagnated. 
In such cases what may be termed stagnation-pneumonia (or hy- 
postatic pneumonia — a less correct term) is the physiological 
result; some might prefer to term it pathological. We will nof 
discuss straws. In such a case we ha\e another xery vascular 
tissue to consider, and that is the mucosa of the bronchioles ; 
this also is engorged, and as in the lung a serous effusion takes 
place into the alveoli, so in the bronchioles, the same occurs, 
leading to a complete obstruction of the circulation of the air ; 
