“…The possible causes of the lung shadows appearing in the radiograph are interstitial haematoma (Major, 1956), acute localized oedema (Zenker, 1956; Barrett, 1960), patchy confluent atelectasis (Major, 1956), and intra-alveolar haemorrhage (Sealy, 1949). Probably all the above factors play some part in the production of the lung opacities.…”