This little monograph is based partly on a review of the literature (377 titles) and partly on the author's own experience. The whole book makes interesting reading and covers the subject very well. The author makes no new contribution to etiology but gives an interesting discussion of the speculations in the field.
The wealth of material makes the reader realize the vast proliferation of medical knowledge which has recently taken place. Perhaps the medical library of the future will consist of a series of monographs, each dealing with one disease. The reviewer has no answer for this problem.