Chronic alcohol poisoning, by devitalising the tissues, weakens the power of the body to ward off microbial attacks. Alcohol affects the structure of the red corpuscles of the blood, and diminishes their power of resistance towards hæmolytic agents (Laitinen). It exerts a paralysing effect upon the leucocytes, and thus interferes with their functions as destroyers of infective micro-organisms that may have gained access to the blood. On the blood-plasma, also, alcohol, has an injurious action, bringing about a decrease in its bactericidal power. The obvious conclusion from these observations is that alcohol lessens the ability of the blood to combat disease. Indeed, as regards its effects upon the leucocytes, Horsley and Sturge remark that "the seriousness of this adverse influence . . . cannot be over-estimated. Herein lies the explanation of many infections, many prolonged illnesses, much chronic ill-health, and many premature deaths."1 A slight general depressing influence such as a chill or a local injury may be most dangerous to a chronic alcoholic; whereas upon a healthy individual there might be no harmful effect even if micro-organisms were present, because the vital reaction of the normal healthy tissues would prevent a general infection.