The third edition of this work differs from the second by such changes as seem necessary, only those procedures having some extended usage being introduced. The Wassermann reaction is is more fully explained and sulphemoglobinemia is discussed for the first time. A full account of the use of alkaline hypochlorid solutions in sputum examination (the antiformin method) is given and a number of the recently devised methods for determining the functional activity of the gastro-intestinal tract are introduced. An especially commendable feature of the book is the chapter on parasites, which is unusually complete and will be welcomed by many who have had difficulty in finding desired information on this subject. The book is handsomely illustrated and well deserves a continuation of the favor with which it has been received.