29 
testinal and hepatic lesions but severe pulmonary and 
air sac disease. From three of these B. pyocyaneous 
was isolated and from one the B. psittacosis as well. 
It seems as if there were a sudden outbreak of the disease 
which carried off six birds in a hurry, whereupon the 
virulence of the agent settled a little to moderate sev- 
erity, and that in five animals a mixed infection with 
B. pyocyaneous, chiefly in the air sacs, took place. 
Shortly after we were aware that a communicable 
disease had struck the parrot house, all birds were re- 
moved, the sound ones to separate cages along the walk, 
the droopy ones to the Laboratory, and the exhibition 
cages cleaned by flame and paint. The sick birds were 
treated, half by aspirin, half by aromatic sulphuric 
acid, in the drinking water. We cannot say that this 
treatment had any effect since two of the eight died. 
I wish to call attention to the anatomy of the lesions 
in the organs of the birds dying from full-fledged psit- 
tacosis since they are different from other avian lesions. 
It is noteworthy that the cases in which these "tubercles " 
were best displayed gave the cultures of the bacillus. 
Example of histological notes: — 
Microscopical section of lung shows the organ nearly obliterated 
by pneumonia and congestion. Some ends of bronchi seen, few having 
extensive exudative inflammation. Secondary alveoli for the most part 
open whilst the primaries are occupied by round, polynuclear and RBC 
in which mass epithelia are difficult to detect. Some secondaries show 
edema, others swollen epithelia, still others mixture of these with round 
cells. All vessels full and around them is a mantle of large solidly stain- 
ing mononuclears. Here and there one can find a round group of large 
mononuclears with deeply staining nuclei, possibly vascular endothelia, 
with pigment and other granules. These "tubercles" are apparently, 
signfiicant because they can be found in intestinal mucosa, spleen, and 
elsewhere. Liver capsule is negative aside from many cells beneath it. 
Liver columns distinct because of separation, cells slightly granular, do 
not stain well and contain fine dark pigment granules. Capillaries show 
many small round and a few red blood cells. Kupffer cells not prominent. 
Blood vessels well filled but not grossly distended. Noteworthy change 
is found near vessels in definite cellular groups. These collections unlike 
those in the lung and elsewhere, are made up of several kinds of deeply- 
stained cells, mostly round mononuclears but also some granular eosi- 
nophils and polys; a few endothelioid cells are included. The groups 
are not definitely outlined but do not radiate or spread far. Spleen is 
made up of a diffuse small mononuclear tissue irregularly dotted with 
trabecular, moderately large vessels, small hemorrhages and cell groups 
like those seen in the lung. The last are, however, in this organ in all 
