Skin Physician to the Metropolitan, Evelina and Acton Hospitals It is now well recognized that penicillin is no panacea, but nevertheless it is a remarkable drug, and clinicians in every branch of medicine have good reason to be thankful for its usefulness in their own spheres. It is superior to the sulphonamides in that it has a greater range of effectiveness against bacterial diseases, in that it is virtually non-toxic, in that it rarely causes sensitization, in that its action is not inhibited by serum, pus or blood. Certain bacteria are highly susceptible to penicillin, and others less so, while there is unfortunately a long list of' insusceptible organisms. The Medical Research Council' list the principal bacteria as follows.