From the Asian Review:
This is a translation by the author of his Dutch ''Handboek der Indische Klankleer'' (Handbook of Indian Phonetics), with alterations and additions. It is a lucid, handy and comprehensive review of the subject, so arranged as to form an admirable text-book for the study of Aryan Comparative Philology. It is perhaps to be regretted that the author has omitted Lithuanian and Slavonic, and has made only scanty references to Iranic and Celtic. It may he, as he says, that these groups are not so generally studied as Greek, Teutonic and Latin, but they often (especially Lithuanian) supply forms which are of the greatest value for deciding difficult points of Aryan sound-lore. The only other objection that can be urged is that in some of the most obscure and knotty questions instead of stating the case fully, reference is made to the writings of other philologists, which may not always be accessible to the student. Grimm's and Verner's laws are assumed, not explained.* The work is thus more suited for a text-book to be used in a class or lecture room, where the references and the points which are taken for granted rather than explained, can be orally supplied by the lecturer, than for private study. As a class-book nothing more excellent, or more thoroughly up to date, can be imagined.
* The comparatively recent discovery of the middle gutturals, and the recognition of the true position and relations of the palatals demand a fuller exposition than is here given, and the same may be said of the question as to the priority of the more varied vowel system of the European language groups over the simpler system of the Asiatic.