G64 SUMMARY OF CURRENT RESEARCHES RELATING TO 



is very conveniently performed. A dropping apparatus is added for 

 moistening the knife with 70 p.c. alcohol in the cutting of celloidin 

 sections. ' The alcohol reservoir is rotatory about the supporting axis, 

 and the outilow tube is set excentrically for the adjustment of the 

 delivery. This dropping apparatus is secured to the knife-block, and 

 moves with it (tig. 157). 



Arndt's Double Saw.* — The introduction of this auxiliary, which 

 was noticed in this Journal f a few years ago, has been found so useful 

 that the inventor has brought out an improved form. It is intended 

 for preparing microscopic sections from hard objects. The working 

 space of the saw has now been increased to 6*5 cm., and there are also 

 other improvements. 



t r (4) Staining^and ^Injecting. 



Differential Stain for Gonococcus.^ — B- Leszczynski employs the 

 following method : cover slip preparations are made from the pus diluted 

 with water in the usual way, and after fixing in the flame are treated for 

 60 seconds with thionin solution (sol. sat. aq. thionin 10 c.cm. ; aq. dest. 

 88 c.cm. ; acid carbol. liquef. 2 c.cm.) and washed in water. Then treat 

 for 60 seconds in picric acid solution (sol. sat. aq. acid picric; sol. aq. 

 caustic potash 1 : 1000 ; aa 50 c.cm.). Without washing in water, treat 

 for 5 seconds with absolute alcohol ; wash in water, dry, and mount in 

 balsam. 



The protoplasm of the pus cells is stained straw-yellow and the nuclei 

 red-violet, the gonococci appearing as black sharply contoured diplococci, 

 the other bacteria are yellowish-red to pinkish-red. The extra- cellular 

 cocci and those lying deeply in the protoplasm of the cells are often 

 not stained in a characteristic manner. 



Persio-acetic Acid as a Stain for Vegetable Tissue.§— G. Beck 

 von Managetta recommends a new pigment, Persio, for staining vegetable 

 tissue. It is a red indigo, and is much like Orseille in origin and com- 

 position. It is a purple powder, easily soluble in water and acetic acid, 

 and little or not at all in alcohol. As persio-acetic acid it is extremely 

 valuable, a strong solution staining deeply in 1-2 minutes. The stained 

 sections may be mounted in glycerin, potassium acetate, and Venetian 

 turpentine, by all of which the tone is advantageously altered. Persio- 

 acetic acid will combine with other pigments. The author mentions 

 combinations with nuclear black, nigrosin, methyl-green, and gentian- 

 violet. 



New Method of Rapid Staining Nervous Tissue with Gold 

 Chloride.||— B. de Nabias fixes the tissue in any solution which allows 

 after-treatment with iodine. The sections on the slide are dehydrated, 

 and then immersed in Gram's iodine solution until they become yellow. 

 After washing in distilled water they are placed in 1 p.c. gold chloride 



* Zeitschr. wiss. Mikrosk., xxi. (1904) pp. 104-13 (5 figs.), 

 t J.R.M.S. 1902, p. 112. 



X Centralbl. Bakt. Ref., l t9 Abt., xxxyi. (1905) p. 692. 



§ SB. Deutsch. Naturwiss. Vereins f. Bohmen, "Lotos," 1904, No. 7. See alio 

 Zeitschr. wiss. Mikrosk., xxii. (1905) pp. 166-8. 

 II C. R. Soc. Biol., lvi. (1904) p. 426. 



