THE PHYSIOLOGICAL EFFECTS AND FATE OF CYANOGEN CHLORIDE

1. An analysis of the physiological effects of cyanogen chloride is given. These effects closely resemble those of hydrocyanic acid: in addition there is a local effect on the respiratory passages, resulting in broncho‐constriction and ultimately in damage, when the vapour is inhaled. 2. Blood, or red corpuscles, rapidly converts cyanogen chloride into hydrocyanic acid. Serum also rapidly destroys cyanogen chloride, but without formation of hydrocyanic acid. 3. Conversion of CNCI into HCN by blood is not quantitative. In vitro the per cent. conversion is about 30: for isolated red cells it may be more, and it may be more in vivo 4. When CNCI is inhaled, HCN can be immediately identified in the blood, and in amount comparable with that detectable when comparably toxic concentrations of HCN are breathed. 5. It is concluded that the lethal effects of CNCI are due to the formation of HCN, and that other actions are subsidiary. 6. Evidence is given that both HCN and CNCI are ultimately converted into HCNS in the body. We wish to thank the Ministry of Supply for providing the facilities for carrying out this investigation, and for giving permission for its publication.