260 movement in the hæmatozoa-viz., the amoeboid movement, the movement of the flagella, and the movement of the pigment. He believes that the individual forms of parasites present true species which do not undergo a transformation into other forms. As regards the melanæmia, so characteristic of malaria, Dr. Mannaberg writes: " The melansemia. is explained convincingly and indubitably by the fact that the parasites transform the haemoglobin by which they are nourished by means of their

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... m into melanin. Melanin is, therefore, nothing but the undigested residue of nourishment which the parasites form and heap up in their bodies ; the granules and rods can be conveniently termed faecal matter, notwithstanding that they are not thrown out." The anæmia of the disease is easily explained by the fact that the red blood-corpuscles are consumed and destroyed by the malarial parasites. This volume will prove a valuable addition to the. admirable series with which the New Sydenham Society is enriching medical literature. International Clinics. Edited THESE handsome and well-printed volumes, which are issued with great regularity every quarter, contain a vast amount of instructive and readable matter. The range of subjects is as wide as that of medicine itself, and the lectures upon them are gathered from the clinical schools on both sides of the Atlantic. The publication of such a repertory of bedside experience cannot fail to exercise a marked influence on thought and practice, whilst the fact that a venture of this magnitude should have attained its fourth year of existence demonstrates that its volumes have obtained a recognised and sure place in periodical medical literature. Each volume contains some fifty or sixty lectures and commentaries upon cases of disease ; a certain number of the former are elaborated into general disquisitions, but the majority are purely clinicalthat is, are based upon cases under observation at the time of the delivery of the lecture. In our opinion, this is the only right form into which a clinical lecture should be cast. It does not and ought not to aim at being an exhaustive survey of the topic with which it deals-such a review should be reserved for the monograph or thesis; but it should bring out in clear detail the clnical facts aittaching to the patient and deduce therefrom the lessons they convey. In perusing these volumes we had marked for especial comment several of the interesting lectures they contain, but on reflection it has seemed that such criticism would be unnecessary. on Gall-stones ; Mr. Bland Sutton, on Lymphatic Œdema ; Mr. Tiffany, on Cataract (two lectures full of detail as to pathology and treatment) ; 21. P. Budin, on Alimentation of Infants. A list which includes such contributions to medicine and surgery exemplifies the variety and interest of the subject and the value of the sources from which they are derived. gandbucJa der Physiologischen Optik. Von H. v. HELM-HOLTZ. 2te Auflage; achte Lieferung. (Handbook of Physiological Optics. Bv H. v. HELMHOLTZ. Second Physiological Optics. By H. v. HELMHOLTZ. Second Edition, Eighth Part.) Hamburg und Leipzig : Leopold Voss. 1894. Pip.561-640. WE welcome with pleasure the eighth part of Professor Helmholtz's handbook, which we suppose will be completed in about four more parts. May we venture to hope that they will succeed each other a trifle more speedily than those which have been lately issued? ? Eight years have elapsed since the appearance of the first part of this second edition and two years since the issue of the seventh part. The additions that have been made scarcely seem sufficient to require two years' or even two months' work for their composition. Many of the eighty pages are unaltered, and though doubtless Professor Helmholtz's time is fully occupied, yet the lapse of many years between the commencement and the conclusion of even a standard work impairs its value as a representation of the state of knowledge at the time it is written. The present part is occupied with the subject of visual perceptions. The chief new sections are devoted to the subjective sensations of Professor Koenig and to a consideration of the psychological views of Kant, more particularly in regard to the question whether the objects of our visual perceptions as form and colour are realities or merely modes of thought dependent on our structural organisation. Defects in Plumbing and Dmainacle Work. By FRANCIS VACHBB. Manchester and London: John Heywood. 1894. THIS little work consists of the record of a collection of blunders in sanitary engineering, gathered by the author either in his daily work or sent to him by correspondents engaged in a similar field of employment. In all about 103 cases are instanced which display errors either in rainconducting, trapping yard and area drains, sink waste-pipes, bath and lavatory waste, and overflow-pipes, watercloset fittings, ventilating soilpipes, house drains, or domestic cisterns and hot and cold water apparatus. Many of these defects evidently arose from ignorance, but a good number can only be attributed to a wanton carelessness and scamping of work. Not a few were met with in houses comparatively recently erected, and they therefore afford instructive reading as to the amount of supervision exercised by some sanitary authorities upon building operations conducted in their district. The work is so simply written, and illustrated by such a profusion of diagrams, that we feel confident it will be within the range of every class of reader. We cordially recommend it to medical officers of health and sanitary inspectors, but particularly to plumbers, who will earn for themselves the thanks of a grateful public if they will only read Mr. Vacher's book and avoid "how not to do it." New Inventions. WOOD PAVING OF STREETS. IN reference to our recent remarks on the wood paving of streets, specimens of a hard wood of Western Australia have been submitted to us. In a rough experiment made in our Laboratory a brick of this wood, when soaked in water for an hour, increased in weight by 4 per cent. Similarly, a block of ordinary deal absorbed over 8 per cent. in the same time. Thus the specimen submitted to us would appear