This is an elaboration of the first edition. It is splendidly written and illustrated. The author describes in great detail the various tests, qualitative and quantitative, for duodenal contents. The colorimetric methods for diagnosis of biliary and pancreatic disease are hampered by so many variations that may occur in a normal person without any evidence of disease that one would be reluctant to hazard a diagnosis merely on color changes in the duodenal contents. The method of duodenal feeding may be better done by the use of a vacuum bottle and rectal drip rather than the syringe-glass method. There are numerous other instruments, measured and described, which are of distinct value.