Salts and Their Reactions

wvhich aire occupied by illustrations, hut the author has Nvritten succinctly without alnyloss of clarity, ani(d he can coinveymnuch valuable information in very little space. H-lis illustrations halve been chosen wisely, and their quality is of a remarkably high standard. There is no notable omission, withi the single exception, perhaps, of an account of the important changes in the only pa-t of the nervous system which can be directly obseive(d by the student, namely, the retina. -fthe reviewer is of the opinion that a short chapter oIn the several varieties of ''optic nieuiitis'' and their significancc would lhave been a valuable addition to the hook. The teachling i thoioughliy sound. No space is wasted on the discussioin of etiological hypotheses which benefit neither stutdent nor patient. ()n the other hand, there is a shrewd cr-iticism of the signiticance of structtiral changes as a means of classification on an etiological basis. III this connection it is inte-estinig to note that the author has classified post-vaccinal encephalitis ill the group of diseases of unknown etiology; and in the present state of knowledge that seems to be the best place to put it. Certainly the structural changes which are observed in this affection clo not conform to those of ainy known virus disease. Typographical errors are fews and far between. The book can be w-armly recommeilded to all students of the pathology of the nervous system. It should go far to realize the author's hope that "through familiarity wsith the pathology of the Xvarious lesions the stu(lent will be tempted to envisage \ hat is actually happening in the niervous tissues, and to take a more active interest in the elucidation of possible etiological factors.''