364 SUMMAKY OF CUEiiENT EESEARCHBS RELATING TO 



Hoyer's Method of Microscopic Injection.* — B. Mozejko contri- 

 butes a note upon this method. G-lass cannulas drawn out carefully 

 and evenly to a fine point and bent at a right-ans;le are used. These are 

 filled with injection material by means of a pipette. For finest work 

 Griibler's Berlin blue, for coarser work some of Lefranc's preparations 

 are employed. The open end of the cannula is then connected by means 

 of a rubber tube with a gas-pressure cylinder. The object to be injected 

 is dipped in 70 p.c. alcohol containing a few drops of cocaine or chlore- 

 tone, and then placed on a glass slide or a Petri dish under a binocular 

 microscope. The end of the cannula is pushed through the integument 

 and into the desired vessel ; the stopcock of the cylinder is turned so 

 that the injection may be made at constant pressure. By this means 

 a threefold injection — arteries, veins, and lymphatics — of a frog embryo 

 may be accomplished. The preparations are fixed in formalin or 

 formalin-acetic acid, and preserved in 70 p.c. alcohol. 



New Freezing- Microtome.f — L. Ssobolew discusses a new model 

 of student's freezing microtome made by the firm of Sartorius in 

 Gottingen. He commends the solidity of construction, and the in- 

 creased range of excursion of the knife. He also finds that there are 

 improvements in the automatic adjustments, and that the ether spray is 

 more conveniently arranged. On the other hand, he finds that the 

 arrangements for fixing the apparatus to the table are unsatisfactory, and 

 suggests that the surface of contact should be larger and rougher. 

 Improvements in the ether spray with regard to the disposition of the 

 tubes are suggested. The earlier instruments were more conveniently 

 adjusted for the cutting of 15, 20 and 25 /x, sections. 



(4) Staining and Injecting. 



Staining Mitochondria of Cancer-cells.| — M. Favre and C. Regaud 

 employ the following technique for demonstrating the presence of mito- 

 chondria in cancer-cells. Pieces taken from the breast intra vitam were 

 fixed in a mixture of formalin, 20 vols., and in a 3 p.c. solution of 

 bichromate of potassium, 80 vols. After this the pieces were mordanted 

 in 3 p.c. potassium bichromate for a variable period, and the sections 

 stained with iron-h^ematoxylin. The fixation time for the specimens 

 described is given as three days ; the mordanting time fifteen days. 

 The authors point out that it is necessary to test every specimen, in 

 order to ascertain the optimum mordanting time. 



Demonstrating the Microbe of Peripneumonia of Cattle. § — E. J. 

 Martzinovski found the best way to stain this organism was to stain 

 unfixed smears with Giemsa's solution for from 4 to 6 hours. Carbol 

 fuchsin. Gram, and the Indian ink methods were failures. Micro- 

 scopical examination under magnifications of not less than 1000 showed 

 large numbers of rodlets, the majority being coccobaciilary in form. 

 The organism is very pleomorphic, many rodlets being swollen in the 



* Zeitschr. wiss. Mikrosk., xxviii. (1912) pp. 427-31. 

 t Zeitschr. wiss. Mikrosk., xxviii. (1912) pp. 448-50. 

 X C.R. Soc. Biol., Ixxi. (1911) pp. 658-61 (6 figs.). 

 § Ann. Inst. Pasteur, xxv. (1911) pp. 914-17 (1 pi.). 



