Digest of Current Literature. 77 



TALS. — Em. Bertrand. — Comptes Rcndus, December 17th, 1877. This 

 is really an ingenious arrangement, and appears to be quite practicable 

 and accurate. Want of space only prevents us from translating it 

 entire. 



In the eye-piece is placed a cylinder of glass of higher refractive 

 power than balsam. This cylinder is split lengthwise, the surfaces 

 polished and again cemented together with balsam. 



With direct illumination, the field is illuminated equally and a line 

 crosses it. When a crystal, the surface of which is large enough to 

 change the direction of the rays of light, is placed upon the stage, 

 these rays suffer total reflection in the eye-piece cylinder, owing to the 

 film of balsam. 



One can readily understand what the effect would be in this case, 

 and how the instrument is used. It makes a revolving concentric 

 stage unnecessary. 



TRANSPORxmo Living Specimens for the Microscope. — Dr. Pel- 

 letan. — A notice of the enterprise of Mr. T. Bolton, of Birmingham, who, 

 being an industrious collector of objects, has for some time been selling 

 them, and sending them by mail in little glass tubes. A long list of 

 objects, which he supplies, is given. This is certainly of great value to 

 microscopists, but in this country we cannot enjoy such benefits. 



New Model Microscope, of Mr. R. B. Tolles, Boston.— Geo. 

 E. Blackham, M. D., Dunkirk, N. Y. — A detailed description of a 

 stand recently made for the author. 



The "Transporter" of Prof. Monnier.— This is a mounting 

 instrument for placing the cover glass in position. Its use is described. 



July, 1878. 



Lymphatic Hearts. — Prof. Ranvier. — Continued. 



Observations on the Termination of Motor Nerves in the 

 Striated Muscles of the Torpedo Fish, etc. — Continued. 



Preliminary Note on the Development of Blood and Ves- 

 sels. — Drs. V. Brigidi and Al. Tafani. 



These studies, which appear to have been carefully conducted, were 

 made in great part upon the embryo of Cypriitiis aitratiis while living, 

 and this subject the authors consider peculiarly adapted to the work. 

 The germ, freed from the testaceous membrane, may be placed in a 

 cell with a drop of water, covered, and can be long examined without 

 the use of an anaesthetic. We can barely indicate the results of these 

 studies. It is affirmed, and will be more fully shown, in a forthcoming 

 memoir, entitled the " Embryology of Cyprinus auratus," that the blood 

 and vessels have their origin in a special "feuillet" which appears about 

 the second day after fecundation. This the authors designate as the 

 " vascular feuillet," and they thus verify the observations of former 

 students. 



They feel fully justified in saying that the white corpuscles are formed 



