ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 533 



5-10 p.c. formalin, Zenker's, Kultschishky's, Schaudinn's. After 

 treating the material when necessary with potassium iodide and hydric 

 peroxide, the pieces were placed in upgraded alcohols and kept in 80 p.c. 

 alcohol. Pieces of the hardened material not thicker than 2-5 mm. 

 are placed in alcohols downgraded to 30 p.c, and then immersed in 

 1-1 h p.c silver nitrate at 42° C. for 48 to 120 hours. On removal 

 from the thermostat the pieces are washed for one hour in water, and 

 then placed in 3-4 p.c. aqueous solution of pyrogallic acid at room 

 temperature for 15 to 24 hours, or for a similar time in 10-7J p.c. aqueous 

 solution of " Agfa "-Rodinal. To the developer is added 3-4 p.c. 

 formalin. On removal the pieces should be washed in running water 

 for an hour, and then passed through upgraded alcohols to equal parts 

 of alcohol and ether, and afterwards to pure sulphuric ether before 

 imbedding in celloidin. The sections may be mounted at this stage in 

 the usual way, or afterstained with hematoxylin-eosin, hematoxylin 

 fuchsin, methylen-blue and eosin, or the author's own stain for malaria 

 parasites. All the foregoing procedures, from the moment when the 

 pieces Were placed in the brown-glass vessels filled with silver nitrate 

 solution, were carried out in a dark room illuminated with ruby-red 

 glass lamps. 



Thionin and Picric Acid after Silver Impregnation of Spiro- 

 chetes.* — J. Sabrazes and R. Duperie have found that after staining 

 sections of syphilitic organs by Levaditi's method it is advisable to 

 counterstain with carbol-thionin and then treat with picric acid. The 

 " thionine picriquee " method was devised by Sabrazes in 1897. By 

 this combination the spirochetes are well shown against the yellow and 

 green background of this preparation. 



Vanadium-hematoxylin and Picro-Blue-black.f — M. Heidenhain 

 recapitulates the formula of his vanadium-hsematoxylin solution, and 

 refers to his experience of this stain, which he has now used for over 

 15 years. To a freshly prepared - 5 p.c. solution of hematoxylin is 

 added half its volume of a 0*25 p.c. solution of ammonium vanadate. 

 This should be kept in an hermetically sealed vessel and shaken daily 

 until ripe (8 to 10 days). Connective-tissue, cartilage, etc., are blue, 

 blood-corpuscles, nucleoli, and granules yellow, muscle yellowish brown, 

 cell-plasma dark brown. For connective-tissue he finds the following 

 useful : blue-black B, 1 ; picric acid, 400 ; methyl-alcohol, 80; water, 320. 

 This solution may be used or diluted with an equal bulk of water. The 

 stain should Vie used in conjunction with carmalum. 



New Staining Methods.^ — B. Rawitz gives the following formulae : 

 1. Xitro-hematein : Hematein 1 grm. ; aluminium nitrate 10 grin. ; 

 distilled water 250 c.cm. ; glycerin 250 c.cm. The aluminium nitrate 

 is dissolved in the distilled water, the hematein is then added, and the 

 mixture heated on a sand-bath to boiling. When cold the glycerin is 

 added. The solution does not overstain. 



* C.R. Soc. Biol. Paris, Ixvi. (1909) pp. 690-1. 



t Zeitschr. wiss. Mikrosk., sxv. (1909) pp. 401-10. 



j Tom. cit., pp. 385-96 (1 pi.). 



