ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 711 



The plates, most of whicli are coloured, represent the different 

 minerals described in the work as seen under the Microscope, i. e. not 

 isolated but in their natural association in rock sections. These 

 plates are upon a novel and ingenious plan. To indicate each 

 particular mineral in the sections would ordinarily require the use of 

 letters or numerals, interfering with the appearance of the plates. 

 This is avoided by attaching to each plate (at its upper margin) a 

 piece of transparent paper the size of the plate, containing the 

 outlines of the different minerals shown. These outlines being exactly 

 superposed on the plate, and being identified by figures referring to 

 an explanatory table giving the names of the minerals, any one can be 

 at once identified by allowing the transparent sheet to cover the plate. 



Some of the plates are " photoglypts " from sections under the 

 Microscope. In all the plates the principal planes of the Nicols when 

 crossed are supposed to be parallel to the margins of the paper. 

 When not crossed the principal plane of the polarizer is supposed to 

 be vertical. The colours of polarization are those shown by the 

 ordinary thickness of the authors' slides, viz. 'Ol-'OS mm. 



Stirling's Practical Histology.* — This book is divided into two 

 parts — " Introduction " and " Practical Work." 



The first (38 pp.) contains histological requisites, general directions 

 on the use of the Microscope, including making drawings, preparing 

 tissues, cutting sections, staining, mounting, and injecting. 



The second part is arranged under forty-nine separate headings, 

 commencing with blood and ending with the umbilical cord. Each 

 subject is dealt with under distinct sections, " preparation " and 

 *' examination," the latter under high (300) and low (65) powers. The 

 arrangement of this part of the book typographically and otherwise 

 is exceptionally excellent. Another special feature consists in the 

 plates, in which the main features of the chief sections are indicated 

 in outline, it being left for the student to fill in the details, the leading 

 parts of which are indicated in the text. The frontispiece is so filled 

 in with colours as an example. 



Dr. Klein complains f that the author has not acknowledged his 

 indebtedness to the ' Atlas of Histology ' and other books. 



* Stirling, W., ' A Text-book of Practical Histology, -with Outline Plates,' 

 Ivi. and 130 pp., 31 pis. and 27 figs. (4to, London, 1881.) 

 t • Nature,' xxiv. (1881) p. 163. 



