366 
PLEURO-PNEUMONIA IN AUSTRALIA, 
POST-MORTEM APPEARANCES. 
I have opened, and seen opened, some hundreds of'diseased cattle, in 
all stages of pleuro-pneumonia epizootica. Of course I had no means 
of determining exactly the length of time the animals had been ailing. 
That which seemed to he the earliest organic destruction of lung 
consisted of a white, dry, distended, cellular stage. The red corpuscles 
evidently do not now enter the capillaries for the purpose of being 
aerated, though the coloured blood may be seen in all the large vessels. 
In this stage I believe the air-cells to be filled with a kind of steam. 
They will not collapse, even though pressed from without, or else the 
muscular tissue has gone into a spasmodic state. 
However, I found in other parts of the lung watery effusion, which I 
regarded as this steam condensed—a state of lung which led a professor 
of pathology to set down the disease as one of a dropsical nature. 
I have also in the same lung observed congestive stage of pleuro¬ 
pneumonia epizootica, differing from common congestion in this, that 
you cannot press out the blood from the part, and it seems as if turned 
into muscle. 
Taking this in connection with the pale state, one would almost be 
led to suppose that it was not the want of iron nor of the red corpuscles 
carrying that iron, but rather its excessive effusion in some places and 
non effusion in others from local or general causes. 
In the second stage the congestion has gone nearly over the whole of 
the lungs, and the fleshy spots increased in size and number, while the 
cells appear filled with dark, carbonaceous blood and areolar tissue 
filled with lymphy effusion. 
If the congestion be more superficial than deep-seated, the lung 
appears all mottled outside, and you have extensive pleuritic disease 
with effusion of lymph; and the blood drawn from the animal appears 
very black in colour, with a milky-looking substance floating on its top. 
I am inclined to believe that this dark-spotted congestive state is 
caused to a great extent by the improper mode in which the blood has 
been aerated. 
But how to account for the milky matter on the top of the blood I 
do not know. I have before slated my opinion on that subject. 
, The third stage is the marble or liepatized stage. The absorbents 
have been busy at work, clearing out the dark blood from the cells, 
while lymph has been effused in greater quantity in the areolar tissue. 
But in the cells a deposit remains, and that deposit seems principally 
made up of the fibrinous portion of the blood. The capillaries ramify¬ 
ing between rings of trachea are congested in this stage, and much irri¬ 
tation exists round the vocal cords, and in the region of glottal opening. 
All this time the adhesive process has been making rapid progress, so 
that now, when hepatization is complete, the lung has generally become 
firmly attached to the ribs. 
If the animal survives all this, the lymphy effusion continues, and a 
new membrane is formed around the diseased lung. This continues 
until the envelope is complete, and then this disease ceases. But 
another commences, termed the suppurative process. This I have 
explained in another part of my paper. 
In all the animals I opened bad with pleuro-pneumonia epizootica I 
found all the other organs remarkably healthy, except the lungs and 
pleura, except the first case given in my first report. 
For this reason I am inclined to think the per-centage of deaths among 
the present generation will not be great. 
