Apbil 20, 1900.] 



SCIENCE. 



623 



book for Students and Practitioners. By 

 Edward Datis, A.M., M.D., Adjunct Profes- 

 sor of Diseases of the Eye in the New York 

 Post-Graduate Medical School and Hospital, 

 etc., with One Hundred and Nineteen En- 

 gravings, Ninety-seven of which are Original. 

 8vo. Pp. XII, 431. 



This book as indicated in its sub-title is prac- 

 tically a treatise on Ophthalmometry. Replete 

 with illustrative cases showing the most accu- 

 rate and the most certain of the methods that 

 are employed by the author for the examination 

 and correction of errors of refraction, it serves 

 as an excellent clinical guide for both the be- 

 ginner and the experienced practitioner in this 

 particular line of ophthalmic practice. 



Well written, devoid of confusing diagrams, 

 and most comprehensive in its every detail, it 

 can be safely asserted that the book is by far 

 the best exposition of the value and the use of 

 the ophthalmometer that we have in our pos- 

 session at the present time. 



Both the author and the publisher are to be 

 congratulated upon the production of a valuable 

 work. C. A. O. 



SCIENTIFIC JOURNALS AND ARTICLES. 



The Journal of Physical Chemistry, January. 

 ' On the Inversion of the Hepta- and Hexa-hy- 

 drates of Zinc Sulphate in the Clark Cell,' by 

 H. C. Barnes ; ' The Melting Point of Chloral 

 Hydrate,' by C. G. L. Wolf. The conclusion is 

 drawn that but one modification of chloral hy- 

 drate exists in the fused substance and that the 

 observed difierences in melting point are due to 

 dissociation. 'The Relation of the Taste of 

 Acid Salts to their Degree of Dissociation,' by 

 Louis Kahlenberg. The author finds that the 

 sour taste of solutions of acid salts is much 

 stronger than would be accounted for by the 

 theory that acid taste is due to free hydrogen 

 ions. ' The Electro-Chemical Equivalent of Car- 

 bon,' by H. C. Pease. The value for carbon 

 when anode in concentrated sulfuric acid has 

 been already determined ; the author finds the 

 value in fused potassium hydroxid (that is in 

 a Jaques' cell), to be three, as in the acid. 

 Carbon in both these conditions is thus quad- 

 rivalent. In the February number : ' On the 

 Emission and Absorption of Water Vapor 



by Colloidal Matter,' by P. Duhem, an ex- 

 tended mathematical treatment of the sub- 

 ject. ' The Melting-point of Formyl-phenyl- 

 acetic ether,' by C. G. L. Wolf. 'Freez- 

 ing-point Curve for Water containing Hydro- 

 chloric Acid and Phenol,' by J. A. Emery and 

 F. K. Cameron. The depression of the freezing- 

 point of water by hydrochloric acid and phenol 

 is in general an additive effect. ' Note on Bun- 

 sen's Ice Calorimeter,' by J. W. Mellor ; prepa- 

 ration of an air free water and filling the calori- 

 meter therewith. 



In The Osprey for March, Paul Bartsch con- 

 tinues his ' Birds of the Road ' discussing those 

 seen in February and March about Washington. 

 Eugene S. Rolfe describes ' Some Trials of a 

 Field Collector ' and J. P. Norris discourses of 

 the 'Eggs of the Sandhill Crane.' Under the 

 caption ' Biographies of Ornithologists ' Theo- 

 dore Gill contributes a first installment of a 

 welcome sketch of Swainson. The editor prom- 

 ises other biographies and in commenting upon 

 the mercantile value of eggs makes some inter- 

 esting remarks on the ' impulse to collect some- 

 thing ' that seems inborn in man. 



The American Naturalist for March opens with 

 a paper by P. Calvin Mensch ' On the Life His- 

 tory of Autolytus Cornutus and Alternate Gen- 

 eration in Annelids ' in which the author reaches 

 the conclusion that in Autolytus we do not have 

 a sexual generation alternating with an asexual, 

 but a sexual dimorphism. Frank R. Lillie pre- 

 sents ' Some Notes on Regeneration and Regu- 

 lation in Planarians,' and W. W. Norman has 

 some ' Remarks on the San Marcos Salamander, 

 Typhlomolge orathbuni Stejneger' which include 

 some excellent figures of this little salamander. 

 C. F. W. McClure writes ' On the Frequency of 

 Abnormalities in Connection with the Postcaval 

 Vein and its Tributaries in the Domestic Cat 

 {Felis domesticay concluding that breeding ex- 

 periments might give us some clue to their 

 causes. J. A. Allen reviews ' The North Amer- 

 ican Jumping Mice ' and L. Murbach treats of 

 ' Fresh- Water Aquaria. ' The Synopses of North 

 American Invertebrates are continued by Har- 

 riet Richardson who discusses 'The Isopoda.' 

 The balance of the number is devoted to nu- 

 merous reviews of current literature. 



