The problems of infection and its prevention are discussed in a general way. Individual infectious diseases are not considered. The nature and the forms of infection, active immunity, resistance and immunity in relation to heredity, variation on the part of infectious agents with reference to pathogenic action, and epidemiology are the main topics. Either the author is not familiar with recent developments in the prevention of scarlet fever or else he discounts completely their significance, because he lists scarlet fever offhand as an example of a non-preventable disease. The book has particular reference to conditions in Germany and its main object is to stimulate the interest of the younger generation of physicians in infectious diseases, especially their transmission.