November 17, 1892 



NATURE 



51 



a map of small scale, to decide what details must be re- 

 tained because they are essential to a grasp of its broad 

 general structure, and what may be safely eliminated 

 without impairing the comprehensive view. In the 

 map now before us this end has been compassed with 

 consummate skill. It bristles with detail, but there is no- 

 where crowding ; the colours are well contrasted, and so 

 transparent that they do not hide the topography, which 

 is full and clearly printed. 



The richness in detail of the strip of country between 

 Cape Wrath and Loch Torridon marks one scene of the 

 recent work of the Geological Survey. Then follows a 

 broad band of " gneissose and schistose rocks not yet 

 differentiated." A portion of this ground is occupied by 

 the crushed and mangled-out complex of the " Moine 

 schists," but a large part is yet imperfectly explored. To 

 the south-east of the Great Glen we enter again on ground 

 which has been largely worked out by the Geological 

 Survey. We have here a group of various sedimentary 

 deposits in a more or less altered condition, containing 

 sheets of basic igneous rocks. The geological age of this 

 series is not known, and they are provisionally classed as 

 Dalradian. 



The presentation of the results of the work of the Geo- 

 logical Survey in the north-west and central Highlands 

 are the two most conspicuous novelties in the map ; but 

 during its use other corrections and additions, too small 

 to catch the eye on a general view, become noticeable. 

 In the explanatory notes we have a concise summary of 

 the geology of Scotland, and feel that our thanks are due 

 to the author for having put so much into so small a 

 space without in any way sacrificing descriptive clearness. 

 When the time comes for a new version of the map, may 

 the same hand be with us to draw it up, 



A. H. Green. 



MEDICAL MICROSCOPY. 

 Medical Microscopy. A Guide to the Use of the Micro- 

 scope in Medical Practice. By Frank J. Wethered. 

 M.D.(Lond.), &c. With Illustrations. Pp. 412. 

 (London : H. K. Lewis, 1892.) 

 'T^HIS volume, one of Lewis's practical series, bears 

 -»- an ambitious title, and must necessarily traverse a 

 wide and intricate field of medical work. Its appearance 

 is justified by the distinct need existing at the present 

 time for a manual dealing with the various microscopical 

 methods so essential to diagnostic accuracy and rational 

 treatment. 



The subject-matter is arranged in twenty-four chapters ; 

 and as an indication of the scope of the book, we instance 

 some of the headings. The earlier ones treat of the 

 microscope and its accessories, the methods of hardening, 

 decalcifying, embedding, section cutting, staining, and 

 injection of tissues. Then follow others on the examina- 

 tion of tissues, urinary deposits, blood, expectoration, 

 and the detection of micro-organisms, and cutaneous 

 parasites; while the latter chapters deal with the ex- 

 amination of food, water, and with bacteriological 

 methods. In fact, the book is almost an epitome of the 

 course pursued by a student earnestly working with the 

 microscope from the commencement to the end of his 

 NO. 1203, VOL. 47] 



curriculum. The tendency has been, by the specialized 

 character of the primary examinations in late years, to 

 sever in some degree the knowledge obtained in the 

 earlier part of a student's career from the practical 

 application of the same at the bedside. So much is 

 this the case, that it has been deemed advisable in some 

 quarters to introduce new courses of lectures, their aim 

 being to indicate with precision to students those facts in 

 anatomy and physiology which have a distinct clinical 

 value. One of the chief merits of Dr. Wethered's book 

 is that he has therein demonstrated the important re- 

 lationship between histology and morbid anatomy, and 

 has shown that any attempt at acquiring a knowledge of 

 the latter is dependent upon a practical and searching 

 training in the former. 



Moreover, the book is worthy of more detailed criti 

 cism. Necessarily in a first edition there are some points 

 omitted. In speaking of the microscope the author offers 

 a cursory remark on the fine adjustment ; no mention is 

 made of the best pattern, and there are many of an 

 inferior and useless description foisted on students ; nor 

 are there any directions for the precise use of this por- 

 tion of the microscope. In the chapter on " Hardening 

 and Decalcifying Tissues," on p. 35, are found somewell- 

 meant platitudes on the necessity of immediately label- 

 ling specimens ; but at the same time the use of lactic 

 acid as a decalcifying agent is omitted. We have suc- 

 ceeded in completely softening small pieces of bone in 4-7 

 days, and teeth may be cut with the freezing microtome 

 in from two to three weeks. 



With certain statements of the author we venture to 

 disagree. In speaking of the celloidin method he 

 advises that the specimen be placed in equal parts of 

 ether and alcohol previously to being placed in celloidin. 

 A mixture of four parts of ether and one part of absolute 

 alcohol ensures more rapid and complete penetration of 

 the embedding material. Also in using paraffin for this 

 purpose we have found by extensive practice that sec- 

 tions containing a large amount of fibrous tissue are 

 useless after being in the paraffin bath for three to five 

 hours, even at a temperature of 48° C. ; twenty to thirty 

 minutes is ample, provided that the material is properly 

 dehydrated. The chapter on staining is succinct and 

 comprehensive, and we note the usual and indeed only 

 rational classification of stains, as nuclear, general, and 

 selective. Hasmatoxylin still holds the first place, and 

 Delafield's, or as it is miscalled, Grenacher's, is undoubt- 

 edly the best formula. It is here stated that if the sections 

 be overstained, and washing in acid-alcohol be necessary, 

 the colour is not permanent. Our experience is that if 

 after the acid they be washed thoroughly well with " tap 

 water," a very clear nuclear stain results which remains 

 unchanged for years. Gram's method of staining for 

 micro-organisms, with Weigert's modification, is clearly 

 detailed. But here we fail to observe any mention of the 

 brilliant results obtained by the Ehrlich-Biondi method. 

 The employment of rubin for actinomycosis may with 

 confidence be recommended,and the same remark applies 

 to the use of saffranin in bringing out-clearly the nuclear 

 figures in karyokinesis. The chapter on mounting is 

 somewhat tedious and the use of origanum oil in clear- 

 ing celloidin-specimens is not advocated, although it has 

 found general acceptance in Continental laboratories. 



