Digest of Cum' /if Lite rati/ re. 325 



the parts to each other. Contributions to the Technic of 



Injecting, by Dr. Hermann Schafer. The Travelling Micros- 

 cope of Carl Zeiss. — This instrument is illustrated by a fine wood-cut 

 which shows it to be substantially made, as all German stands are, and 

 ver}' compact. The cost is 450 marks for the stand, including four objec- 

 tives and all accessories. 



*^* (Av;. //, 1S79.) — Prof. Abbe's Apertometer, by Dr. Leopold 

 Dippel. — -An excellent description of the apparatus and its use, to which 

 we refer more particularly in another place. The Objective Sys- 

 tem for Homogeneous Immersion, by Carl Zeiss. The Dif- 

 fraction Apparatus and Experiments to Demonstrate the 

 Theory of Prof. Abbe. — Both of these articles are clearly written and 

 of the greatest interest. We reserve them for a more complete analysis, 

 to be given at a future time. 



VTHE AMERICAN JOURNAL OF MICROSCOPY (May, 1879). 

 Surrirella Craticula, an Abnormal Form of Navicula Cus- 



PIDATA, by J. D. Cox. A FEW NOTES ON PaRT III., DiATOMS, 



Edited by Cleve and Moller, Nos. 109-168, by H. L. Smith. 



Some Remarks on Microscopical Manipulation, by Prof. H. L. 

 Smith. — This article relates principally to working with the mechanical 



finger. Practical Hints on the Preparation of Opaque 



Objects, by Geo. E. Fell. The Preparation of Insects for 



Microscopical Examination, by M. J. Underbill. 



V BULLETIN DE LA SOCIETE BELGE DE MICROSCO- 

 PIE {April, 7t?7p).— Lithological Researches upon the Phtha- 



NITES OF THE CARBONIFEROUS LIMESTONES OF BELGIUM, by M. A. 



Renard. 



*.j.* In Zoologischer Anseiger for Februar\' 3d, is a brief account of 

 the de\elopment history of the silk-worm, Boinby.v Jiiori, by Tichomiroff. 

 In the number for February 17th is an excellent article "On some 

 Variations in the Development of the Lower Organisms," by Prof. Wm. 

 Schmankewitsch. Prof. V. Graber contributes to a later number of the 

 same periodical an article on "Amoeboid Epithelium ;" and Dr. W. Mayzel 

 describes the "Process of Segmentation in the Eggs of Worms (Nema- 

 todes)." 



*^* The June number of Greinllea contains the concluding part of Mr. 

 M. C. Cooke's communication on " The Dual Lichen Hypothesis." The 

 result of his examination of this hypothesis may be summed up as follows : 



I. It is not in harmony with existing scientific facts. " The assumption 

 that two separate and distinct organisms are combined in one plant, 

 which, by its own proper system of reproduction, is capable of continuing 

 its species, each individual of its progeny also exhibiting the same phe- 

 nomena of assumed dual existence, is inconsistent." So also is the as- 

 sumption that a fungus is " parasitic upon a smaller and weaker organism." 



