918 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Staining with Rose Bengale, Iodine Green, and Bleu de 

 Lyon.* — Dr. H. Griesbach describes Eose Bengale as a chlorinated 

 tetriodofluoresciu, belonging to the Kesorcinphtalein group ; it is the 

 bluest of all known eosin comj)ounds and resembles fuchsin in 

 shade. If dissolved in water it is very useful for staining 

 chromic acid preparations, e. g. spinal cord, the grey substance of 

 which is stained a deep bluish red, while the white substance is paler ; 

 it is also adajjted for muscles and connective of Yertebrata and 

 Invertebrata, but not satisfactorily for glandular tissues or bones. 



It is especially suited for double and triple staiuings, in conjunc- 

 tion with iodine green, and iodine green and aqueous solution of Bleu 

 de Lyon : the nuclei of the gland cells of the organ of Bojanus, 

 hardened in alcohol, come out emerald green, the protoplasm is un- 

 stained ; cell-membranes and cilia are stained red. Transverse 

 sections of the edge of the foot of Anodonta, from an alcohol specimen, 

 should be washed in distilled water, drawn quickly through a dark 

 solution of Eose Bengale, then washed in pure distilled water and placed 

 for some seconds in iodine green, washed again in distilled water and 

 placed for about five minutes in absolute alcohol, to fix the colour and 

 remove possible excess ; the sections are now drawn two or three 

 times through a solution of Bleu de Lyon made with two parts of 

 absolute alcohol and three of distilled water, transferred to absolute 

 alcohol, clarified in oil of aniseed and mounted in dammar-lac ; the 

 result is very beautiful. 



Carmine Staining.t — " Obersteiner is entitled to the gratitude of 

 all neurologists who, while interested in histological researches, are 

 unable to devote much time to cosmetic experiments. He has made 

 the simple suggestion of heating the staining fluid containing the 

 specimens. Previously, when large sections were to be stained in 

 neutral carmine, one great difficulty encountered had been the fact 

 that specimens hardened for any length of time, however well they 

 might ultimately stain, took the colouring matter up so slowly that 

 many days and even weeks elapsed before the process was complete, 

 and in the meantime the carmine usually precipitated, and the finest 

 specimens were thus rendered valueless. In the laboratory of one of 

 the editors it has been attempted to obviate this by daily changing 

 the staining fluid, which can be done, if proper skill be employed, 

 without injuring the sections. But even with this many failures 

 occur. By subjecting the staining fluid containing the sections to a 

 water-bath heated by a sj)irit-lamp, the finest staining can be 

 accomplished in from one to two hours, and in the case of h hema- 

 toxylin in even less time. The heating of hardened sections does 

 not injure them in the least when the precaution is used of employing 

 a water-bath." 



Stain for Fresh Tissues of Vertebrata.J — The methods recom- 

 mended by Prof. S. Mayer are intended exclusively for fresh or recently 



* Zool. Anzeig., vi. (1883) pp. 172-4. 



t Anier. Journ. Neurology and Paycliiatry, ii. (1883) p. 579. 



X SB. Akad. Wiss. Wieu, Ixxxv. (1882) pp. 69-82 (2 pis.). 



