120 



SUMMARY OF CURRENT RLSEARCHEiS RELATING TO 



a drop of a filtered 1 p.c. solution of diniethyl-paramethylendiainin 

 (base) on a slide with a trace of a colony of the organism, and then 

 adds to it a single loopful of a solution of a naphthol in 1 p.c. NaOH. 

 If the preparation is examined after a minute the fat granules or drops 

 are found to be stained dark blue. They are decolorised, however, with 

 1 p.c. H 2 S0 4 . To show that this reaction is not due to volutin, he uses 

 B. alvei, an organism rich in this substance and fat-free. In this, the 

 reaction did not take place. 



Gonococci Staining.* — A. Pappenheim advocates the use of a 

 methyl-green and pyronin mixture for the staining of gonococci and for 

 their differentiation from the cell nucleus. The action of this staining 

 mixture depends on the aversion of methyl-green to bacteria, and on 

 its affinity for the cell nucleus, whilst pyronin being a weak stain only 

 affects the nucleus if added in excess. The result is a blue-green 

 nucleus and red cocci. If it is desired to stain also the protoplasm of 

 the cell, an acid stain, such as eosin, may be added to the mixture. 



Modification of Gram's Method.f — Nicolle has employed instead 

 of the ordinary Oram's solution, one containing bromine 1 grm., potas- 

 sium bromide 3 grm., water 100 grm. Over the former it has no 

 advantage, but the results in each case appear to be identical. 



Method of Staining the Protozoal Parasites 

 of the Blood.J — Laveran suggests the following 

 modification of Giemsa's staining method § for the 

 malaria parasite. Cover-glass preparations are 

 stained for ten minutes with eosin (1 : 1000) 2 c.cm., 

 distilled water 8 c.cm., azur (1 : 100) 1 c.cm. A 

 drop of a 5 p.c. solution of tannin is then placed 

 on the film and allowed to act for 2 to 3 minutes. 

 The film is then washed and dried. The author 

 finds this method useful when dealing with material 

 which is not fresh. 



(5) Mounting-, including- Slides, Preservative 

 Fluids, &c. 



Improved Mounting Clip.||— S. E. Dowdy has 

 devised the following form of clip or press by which 

 central pressure, which is completely under control, 

 may be readily obtained (fig. 21). 



A B C is a stout piece of wire bent into a circle 



at right angles to the upright A B at C. D is a 



Fig. 21. screw, having at its end a flat circular metal 



button at E, which rotates, independently of the 



sere on the pin F. In use, a freshly prepared Canada balsam slide 



is placed on the circle C, and the screw L) rotated until the button or 



* Monatsbefte f. prakt. Derinat, April, 1903. 

 fief., xxxiv. (1903) pp. 20-1. 



See also Centralbl. Bakt. l ,e Abt. 



t C. E Soc. Biol., No. 10, 1903. See also Centralbl. Bakt., xxxiv. (1903) pp. 78-9. 

 X Op. cit.., No. 9. 1903. See also Centralbl. Bakt. Ref., xxxiv. (1903) p. 78. 

 § Centralbl. Bakt., xxxii. p. 307. 

 || English Mechanic, lxxviii. (1T03) p. 337 (I fig.). 



