ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 633 



(2) Preparing Objects. 



Studying the Maturation and Fecundation of the Mammalian 

 "Egg* — H. Lams and J. Doorme used white mice and guinea-pigs 

 in their research. The ovaries, tubes, and uterine cornua, removed 

 under an anaesthetic, were at once placed in some fixative, Flemming, 

 Benda, and Hermann giving the best results. After hardening in up- 

 graded alcohols, paraffin sections 2-5 /x were made with a Minot 

 microtome. Most of the sections were stained with Heidenhain's 

 hematoxylin. For demonstrating mitochrondria, Benda's method was 

 adopted, the fixative being a modified Flemming (1 p.c. chromic acid 

 15 c.cm., 2 p.c. osmic acid 4 c.cm., o drops glacial acetic acid). After a 

 long immersion in the fixative the pieces were transferred to a solution 

 consisting of equal parts of pyroligneous acetic acid and chromic acid 

 solution, then to 2 p.c. bichromate of potash. After washing and 

 dehydrating, the pieces were imbedded in paraffin. The sections were 

 mordanted for some hours in a 4 p.c. solution of iron-alum, and then 

 in a solution of sulphalizarinate of soda. After this, they were hot-stained 

 in freshly prepared crystal-violet solution. The sections were differen- 

 tiated in ;^0 p.c. acetic acid, and after drying were passed through 

 acetone, oil of bergamot, and xylol to balsam. 



Mitochondria are also stainable by Benda's method. 



(3) Cutting-, including- Imbedding and Microtomes. 



New Method of Making Celloidin Serial Sections. f — W. Rubasch- 

 kin adopts the following procedure. He uses albumen-glycerin in the 

 proportion of 2 : 1 for sticking the sections to the slide. While cutting, 

 the sections are temporarily arranged on the back of the knife to the 

 handle, and when a sufficient number has been made they are removed 

 to the slide. It is important that every section should be quite flat and 

 without creases ; they are easily smoothed out by means of a Ijrush and 

 gentle pressure. When satisfactorily arranged on the slide they are 

 covered with a mixture of equal parts of clove-oil and anilin-oil. When 

 the sections are quite clear and transparent, which will be in from 3-5 

 minutes, the oil is poured off and the slide immersed in 90° alcohol to 

 remove the remains of the oily mixture. The slides are then removed 

 to 70° alcohol and kept there till required. If it be desired to remove 

 the celloidin, the slides are placed in 96" or absolute alcohol, and after- 

 wards in a mixture of equal parts of alcohol and ether. When the 

 celloidin is dissolved out, the slides are passed through 96° to 70° 

 alcohol, after which they can be submitted to any further treatment. 



(4) Staining and Injecting, 



New Injection Apparatus.^ — W. Lindemann, having experienced 

 the desirability of an injection apparatus which should work at constant 

 pressure, has designed that shown in fig. 106. A is an injection pipette 

 which acts either as an air-chamber or as a reservoir for the injection 



* Archiv Biologie, xxiii. (1907) pp. 259-365 ^3 pis.). 



t Anat. Anzeig., xxxi. (1907) pp. 30-1. 



X Zeitschr. wiss. Mikrosk., xxiii. (1906) pp. 427-30 (1 fig.). 



