250 SUMMARY OF CURRENT RESEARCHES RELATING TO 



(2) Preparing Objects. 



Simultaneous Fixing and Staining.* — For the demonstration of 

 mast-cells, F. Strecker recommends a fixing and staining bath, containing 

 100 parts of 40 p.c. formalin, 100 parts of 90 p.c alcohol, and 6 parts of 

 toluidin-blue (Griibler). Pieces of tissue remain in this bath for one or 

 more days, according to size, and are then transferred to 70 p.c. alcohol, 

 raised rapidly through the alcohols, cleared in benzol, and embedded in 

 paraffin. 



(8) Cutting-, including- Embedding and Microtomes. 



New Brain Methods.! — E. Venderovic describes an improved method 

 for cutting large sections of brain by means of the large submerged 

 miciotome. The brain, after three weeks or more in 5 p.c. formalin, is 

 divided in two portions, so as to provide a flat surface for fixing to the 

 microtome plate. This surface is dried with filter-paper. The micro- 

 tome plate is gently warmed and coated with a thin layer of paraffin 

 (melting point 47° C). When this has solidified, the cut surface of the 

 brain is applied to the plate, and hielted paraffin is applied to the side of 

 the brain to a height of 1 cm. Above this point the organ is free from 

 the fixing material. After about half an hour the paraffin has set hard 

 and the cutting begins. The slices should have a thickness of h cm. 

 It is unnecessary to fill the microtome with water. Cutting of the lower 

 section is facilitated if the hand be gently pressed upon the top of the 

 brain. These slices are then washed for 24 hours in distilled water 

 to remove formalin. They are then placed upon glass plates with several 

 layers of filter-paper on either side of each slice, and introduced into a 

 cylinder for the osmic acid process. After remaining for a month or so 

 in contact with Busch's osmic solution, they are washed for ten days in 

 running water, rapidly dehydrated, and then placed for one day in thin, 

 aud one day in thick celloidin solution. • The slices are then replaced 

 exactly in their original relation to one another and treated with chloro- 

 form vapour. The celloidin block so prepared is cut in sections of a 

 thickness of 20 /x. These sections are placed on tissue paper, heated 

 with alcohol, dried with filter paper, cleared in xylol and mounted in 

 paraffin. 



Graphic Reconstruction in Oblique Positions. t — N. Odhner de- 

 scribee a method of graphic reconstruction, which has the advantages of 

 simplicity and speed of execution in comparison with methods of projec- 

 tion or plastic reconstruction. By this method, objects of any form can 

 be observed in any desired magnification in any plane. The method is 

 most valuable in embryological studies. The author illustrates his 

 method by describing its applicaiion to the study of the developing 

 upper jaw. 



Manipulation of Serial Sections. § — In previous communications, 

 H. Strasser has given accounts of his method of using strips of paper 

 to facilitate work with serial sections. The sections as they are cut 



* Zeitschr. wiss. Mikrosk., xxviii. (1911) pp. 268-70. 



t Anat. Anzeig., xxxix. (1911) pp. 414-23. 



+ Anat. Anzeig., xxxix. (1911) pp. 273-81. 



§ Zeitschr. wiss. Mikrosk., xxvii. (1910) pp. 339-44. 



