DK. SCHACHT, ON THE MICROSCOPE. 210 



contaius and distributes air, whilst the tbniier is filled with au uerlftrous 

 fluid, which can scarcely be called blood, the distribution of nutritiue ma- 

 terials being accomplished in both cases by the fluid of the ' general cavity 

 of the body.' 



In his account of the sexuality of the Cryptogamia, Dr. 

 Carpenter has embodied the most recent researclies on this 

 highly-interesting subject. Every lover of natural history, 

 every student of biology, should be possessed of this new 

 volume by Dr. Carpenter. 



The Microscope and its application to Vegetable Anatomy and 

 Physiology. By Dr. Hermann Schacht. Edited by Frederick 

 CuRREY, M.A. Second Edition. Hlghley. Loudon. 



The fact of this book having reached a second edition justifies 

 the good opinion we have expressed of it on two previous 

 occasions. Mr. Currey has taken the opportunity of adding 

 some new matter, which has very considerably improved this 

 edition. Four chapters have been added at the beginning of 

 the book ; the first of which relates to some elementary prin- 

 ciples of optics essential to a proper comprehension of the 

 microscope ; the second contains a description of different 

 kinds of English microscopes, including as far as is necessary 

 the details of their different parts ; the third contains an 

 account of the accessory apparatus and chemical reagents 

 necessary for microscopical investigations in botany ; and the 

 fourth relates to the preservation of specimens. Besides these 

 chapters by the editor, Dr. Schacht lias furnished a quantity 

 of new matter in manuscript, being the result of his investi- 

 gations since the last German edition of his work was pub- 

 lished in 1852. 



The whole of the new matter of this volume will be found 

 interesting to the vegetable microscopist ; and we select as 

 examples of the value of the added matter, one extract on in- 

 struments and another on microscopic structure. 



Disseciing Microscope. — There are many different sorts of dissecting 

 microscopes, which vary according to the fancy of the makers ; but as the 

 principle of all must be the same, it will be sufficient to refer to the 

 accompanying fig. 15, which represents one of the best constructiou by 

 Mr. Ross. The principal points to be attended to in selecting a dissect- 

 ing microscope are to see that the stage is of suflicient size and strength, 

 and that the arrangements for holding the lenses and moving them 

 in diflerent directions, are convenient. In the instrument in fig. 15, 

 the arm at the top which carries the lens-holder has a forward motion by 



