PLATE NO. IV Gangrene of foot caused by vascular thrombosis from chlorine poisoning.

History of case. Gassed by chlorine in 1915 under conditions which could not have induced frost-bite. Severe dyspnoea from pulmonary oedema.

Drawing of foot made on fifth day. Both feet were then anaesthetic, stone cold, and no pulsation could be felt in the dorsalis pedis artery. The right hand also was mottled, cold, and painful. The circulation was restored in a few days with complete recovery, except that two toes became black and shrivelled.

Such arterial thrombosis, of slowly progressive onset, is quite uncommon in the extremities, though it is occasionally seen with phosgene. The obstruction is very rarely so complete as to cause gangrene and death of the tissues. But this drawing of a visible condition is introduced in order to emphasize the fact that an unseen vascular thrombosis of smaller vessels in deeper organs of the body is frequently found with phosgene poisoning. Such thrombosis is revealed by the microscope in fatal cases in the smaller lung vessels, in the kidney, in the mucous membrane of the stomach, and in the brain. Indeed in deaths with prolonged asphyxia from gassing by phosgene the white matter of the brain is often seen to be thickly sown with brownish-red petechial spots around each tiny arterial thrombus. The obstruction to the lung circulation has already been referred to; the kidney thrombosis does not appear to have any serious results; and, except where larger haemorrhages have burst in the brain, the scattered cerebral thrombi do not appear to be of grave clinical import. The petechial areas within the stomach may occasionally become the seat of a superficial ulceration. Large thrombi are sometimes found within the heart, but they also are associated with rather than the cause of the other changes that lead to death.

Plate IV.