THE RESPIRATORY SYSTEM 149 
I have sought to show that protozoa or embryo 
nematodes in the blood might embarrass the lungs to a 
state of congestion, a thought suggested by some findings 
in the London Gardens, but only about ten per cent, of our 
cases of hemic parasitism are accompanied by it. 
The incidence of congestion of the lungs not due to 
stasis as from cardiac diseases, is 2.4 per cent, in mam- 
malian autopsies, in only 7 per cent, of which figure did it 
represent the principal morbid anatomy, whereas in birds 
it occurred to the extent of 7.6 per cent, of postmortems, 
in 17 per cent, of which it was the sole or principal cause 
of death. This seems to bear out the feature of delicacy 
of the pulmonary vascular mechanism in these latter 
animals. This condition seems to be indicated by simple 
dyspnoea in birds, relief for which has occasionally been 
afforded by removal from the exhibition cages and pro- 
tection separately in a warm dry room; this is partly 
hypothetical of course and congestion is to be looked upon 
as serious, particularly in passerine birds. 
Pneumonia. 
Pneumonia as a clinical disease is a relatively un- 
common, although quite serious sporadic condition in 
animals. However accompanying the specific, more or 
less epizootic diseases such as influenza, distemper and 
the choleras it may be a frequent and quite pronounced 
complicating feature of the case. Pneumonia per se has 
exacted a reasonable toll in tliis Garden but unfortunately 
recog-nition being impracticable, diagnosis and treatment 
have not progressed. Nor has it been practicable to group 
our cases pathologically because of the lack of history 
and the difficulty of making bacteriological observations 
at many autopsies. Fortunately we have had practically 
no epizootic pneumonias, an experience shared with other 
gardens judging by their published reports. Etiologi- 
cally, and of course this applies to non-verminous, non- 
mycotic and non-tuberculous cases, the pneumococcus has 
