Chemical control of soda-lime efficiency in circle filters.

NON NOSCERE" continues to be one of the most important aphorisms—if not the most important of all—in contemporary medicine and anaesthetists should never ignore it. The use of elaborate anaesthetic technique entails correlated dangers, which can only be counteracted by minute and profound knowledge of the situation created. Under this heading comes closed circuit respiration, which to-day is so commonly employed that its handicaps are often forgotten. Facilities in blood and plasma transfusion, which frequently accompany good anaesthetical organisation, are capable of disguising many misuses of carbon dioxide absorbers. To ventilate a patient with oxygen is ordinarily a simple matter, but the adequate removal of carbon dioxide may be neglected. In fact, the criteria relied upon to assess the efficiency of carbon dioxide absorption are not entirely satisfactory for the following simple reasons: 1. The best brands of soda-lime when stale produce misleading results. For example, in the hospital stores, the container that was last bought can be incorrectly arranged in front of formerly acquired ones, so that the anaesthetists may later use a very stale soda-lime, supposing it to be fresh. This is more liable to occur in hospitals which buy in bulk. The situation is worse in many countries which must import soda-lime, a painfully long procedure,