ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 675 



Staining Leucoplasts, Protein-granules, Bordered Pit Membranes, 

 and Woody Tissue.* — In his treatise on the morphology and physiology 

 of the vegetable cell, Dr. A. Zimmerman recommends acid fuchsin for 

 staining leucoplasts and chromatophores. After the objects have been 

 placed in a concentrated solution of the dye for some minutes, they are 

 shaken about in a solution of picric acid in 50 per cent, alcohol for one 

 minute, and then washed in 50-70 per cent, spirit. The preparations are 

 mounted in balsam. For the fixation of the protein-granules a saturated 

 solution of picric acid in strong spirit is recommended. When fixed and 

 stained the protein-granules can be mounted at once in balsam. In a 

 mixture of htematoxylin and Bismarck brown, woody membranes are 

 stained brown, the others violet. For showing the membrane of the 

 bordered pits in material preserved in spii'it, gentian-violet is recom- 

 mended. The dye is picked up from a watery solution by this mem- 

 brane, which becomes deeply stained, while others are almost colourless. 

 Next to the bordered pit membrane the middle lamellae stain best. 

 The sections may be examined in oil of cloves and then mounted in 

 balsam. 



New Method for Staining Fibrin and Micro-organisms.t— Prof. C. 

 Weigert has devised a modification of Gram's method in which the 

 alcohol and oil of cloves are replaced by anilin oil. The procedure is 

 as follows: — The section (hardening in spirit) is stained with the anilin- 

 gentian violet solution. The staining may be done either on the slide 

 or in a watch-glass. In the latter case the section must be washed with 

 water or with NaCl solution to remove excess of dye before it is placed 

 on the slide. The section is then mopped up with bibulous paper and 

 the iodine solution dropped on ; when the latter has acted sufficiently 

 the section is again blotted and then covered with a drop of anilin oil, 

 which must be removed several times as it quickly picks up the stain. 

 The section becomes gradually transparent and the anilin oil is removed 

 with xylol and then mounted in balsam. 



If a double stain be desired the additional colour must be imparted 

 before the violet. In this method there is no need to remove the 

 celloidin. By this procedure fungi and pneumonia cocci are more 

 easily demonstrated than by Gram's method, but its principal recom- 

 mendation is the sharp stain it imparts to threads of fibrin. Bacteria 

 and fungi appear quite dark, almost black, the fibrin threads a beautiful 

 blue. 



New Nuclear Stain and Note on Fixation. | — Dr. G. Platner 

 describes a new pigment to which he gives the name nucleus-black. It 

 is imported from Eussia as a black solution, and appears to be a metal 

 base in combination with an organic acid. When used in weak solution 

 it is specially adapted for staining nuclei, nucleoli, and axis cylinders, 

 the protoplasm, connective tissue, and nerve-sheath remaining unstained. 

 If used in concentrated solution the staining is more diffused, but may 

 be reduced by alkalies. Thus five or six drops of liquor ammonife to a 

 watch-glassful of water or a saturated solution of lithium carbonate 

 diluted, if required, with distilled water, are convenient for limiting the 

 stain to the nucleus and showing up the karyokinatic figures. 



* Sep. Eepr. from ' Encyklopsedie der Naturwissenschaften,' Abtbeilung : Hand- 

 buch d. Botanik, Schenk, 1887, 223 pp. Cf. Zeitschr. f. Wiss. Miki-., iv. (1887) 

 pp. 529-30. t Fortschr. d. Med., v. (1887) p. 228. 



J Zeitschr. f. Wiss. Mikr., iv. (1887) pp. 349-52. 



