

ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 373 



be washed for a few seconds in distilled water, and then transferred to 

 the following reducing medium : — Pyrogallic acid 1 grm. ; formalin 

 5 to 10 grm ; distilled water 100 grm., for 24 hours. After a rapid 

 wash the pieces are placed at first in 36 p.c.;alcohol and then in absolute, 

 previous to imbedding in celloidin or paraffin. 



The author * adopts the same procedure for staining nerve-fibrils. 



Preparing Planarian Worms.!— Gr. Marpmann places the worm on 

 a slide by means of a pipette, and then narcotises it with • 5 p.c. eucain. 

 When it no longer responds to the stimulus of a needle, it is killed by 

 pouring over it the following solution : — Sublimate 1 ; salt 1 ; glacial 

 acetic acid 5 ; water 100. The specimen may be stained with picro- 

 carmin and then cleaned up in pure carbolic acid, the latter being re- 

 moved by means of xylol previous to mounting in balsam. These 

 worms are well adapted for showing nerve ramifications when stained by 

 appropriate methods. 



Demonstrating the Structure of Cardiac Fibres.:}: — In his researches 

 on the structure and development of the cardiac fibres in theVerte- 

 brata, F. Marceau fixed the tissue in acetic acid sublimate, using chiefly 

 Zenker's fluid. After from 4 to 24 hours, according to the size of 

 the heart or of the pieces taken, the tissue was transferred to alcohols 

 (30, 50, 70, 80 p.c.) for 2 to 6 hours, and then paraffin sections made. 

 The sections were usually stained with iron hematoxylin, and afterwards 

 contrast-stained with eosin or Bordeaux red. It was found advisable to 

 mordant the sections for 12 to 24 hours in iron alum. In reference to 

 the after-staining with eosin, the writer notes that it is better to use a 

 weak solution and employ it when the iron staining is halfway through, 

 and finish off the iron staining afterwards. 



Heidenhain's hematoxylin and vanadate of ammonia method was 

 also used, but only in a few instances, as there are many difficulties con- 

 nected with it. The hematoxylin and chloride of vanadium method 

 recommended by Wolters was found to be far more easy ; the results 

 were good, but did not differ materially from those of iron hematoxylin. 



In order to obtain good preparations of heart-muscle of birds and 

 mammals, it was found better not to fix the material until three-quarters 

 of an hour had elapsed after the animal was killed. 



For teasing out the fibres 20 p.c. nitric acid was far superior to 

 caustic potash or chromic acid ; the fibres were easily dissociated, and 

 when washed in water, alcohol and glycerin would make excellent per- 

 manent preparations. 



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



New Method for Sticking Celloidin Sections to the Slide.§ — R. 

 Fischel recommends linimentum exsiccans for sticking celloidin sections 

 to the slide. This adhesive is composed of 5 parts tragacanth, 2 parts 

 glycerin, to 100 parts distilled water, and is put up in collapsible tubes. 



* C. R. Soc. Biol, de Paris, lv. (1903) pp. 1565-8. 

 t Zeitschr. angew. Mikrosk., ix.(1903) pp. 328-9. 

 j Ann. Sci. Nat. Zool., xix. (1904) pp. 235-9. 

 § Zeitsch. wiss. Mikr., xx. (1904) pp. 2S8-91. 



