1897. SOME NEW BOOKS. 347 



A New Science. 



Gemmographical Tables for the use of Diamond and Gem Merchants, 

 Jewellers and Students, exhibiting in tabulated form, the distinguishing 

 characteristics of rough and cut stones. By W. J. Lewis Abbott, F.G.S., 

 London : Heywood and Co. Price is. 6d. 



We are inclined to welcome with approval any effort to introduce 

 scientific methods to the notice of jewellers and merchants of precious 

 stones, to whom they are certainly not too famihar, and Mr. Lewis 

 Abbott's tables aim at this desirable result. 



The main features of the various gem-stones are arranged in 

 five tables dealing respectively with their names and colours, their 

 composition and physical properties, their crystalline form, and the 

 colours which they present in the dichroscope. It is to be hoped 

 that these tables will find a use among those for whom they are 

 intended, and will lead them to recognise the practical value of a 

 subject which is taught by the author at the Polytechnic Institute, 

 and apparently with considerable success, though under the 

 unfortunately hybrid name of gemmology. 



The reader must be warned that garnet does not crystalhse in 

 pentagonal dodecahedra, nor spinel in tetrahedra ; neither must he 

 suppose that all the stones included in the formidable list of table i 

 are usually recognised as gem-stones. 



But these are minor blemishes and we may safely commend 

 these tables to the attention of jewellers, feeling sure that they will 

 derive benefit from some shght insight into scientific ways of testing 

 precious stones. 



Histology of the Stomach. 



Lehrbuch der Vergleichenden Mikroskopischen Anatomie der Wirbeltiere. 

 L Der Magen. By Dr. Med. Albert Oppel. 8vo. Pp. viii., 543, with 5 

 plates and many text-figures. Jena : Fischer, 1896. Price 14 Marks. 



It is now forty years since Franz Leydig published his text-book, 

 and since then there has been no serious attempt to bring together in 

 a systematic fashion our accumulated knowledge of comparative micro- 

 scopic anatomy. The delay was natural, and perhaps not to be 

 regretted. The forty years have seen the whole science of anatomy 

 informed by a new principle, and evolution had its youthful wild oats 

 to sow. Vertebrate anatomy, and certainly the details of vertebrate 

 histology, save so far as they bore directly on physiology, were 

 deserted by many acute minds for the new world of promise opened 

 out by comparative embryology and the investigation of the widely 

 diverse invertebrate groups. It seemed an old-fashioned trifling to 

 discuss the minute structural differences to be found in vertebrate 

 mucous coats, when the ancestry of the whole vertebrate group was to 

 be expected from serial sections through a pelagic worm. Probably the 

 best and the worst of this attractive method of investigation are now 

 known, and anatomists are turning again to the closest comparisons 

 between the minutest details of nearly allied forms. And these 500 

 pages on the histology of the vertebrate stomach are a sign of the new 

 direction of anatomical activity. A great bulk of the literature cited 

 is not more than ten years old, and it is plain that the book Avill have 

 its greatest value as a stimulus to still more detailed investigation. 



The author begins by a general account of the conformation of 

 j:he region between the end of the oesophagus and the beginning of 

 the duodenum. He describes the kaleidoscopic varieties of external 

 form into which the region is thrown, and discusses generally the 



