752 SUMMARY OF CURRENT RESEARCHES RELATING TO 



alternately until all trace of the mordant has disappeared. (7) To a 

 saturated solution of silver sulphate and distilled water in equal parts, 

 ffithylanin is added until no precipitate occurs. Silver sulphate solution 

 is then dropped on until a precipitate occurs. The film is then covered 

 with this solution and kept moving until a brown colour appears. It is 

 then washed and examined under a low power, and if flagella be not 

 visible, the process should be repeated and this time with the aid of 

 heat. (8) If flagella are visible, then treat with sublimate 1 : 100, 

 until the brown colour has vanished. (9) Follow this with gold chloride 

 1 to 1000 distilled water, and allow to act for 5 minutes. (10) Next 

 use Zettnow's reducer, 2 p.c. soda solution 4 drops, alcoholic pyrogallic- 

 acid solution (1 : 20) 1 drop ; warm slightly ; dry and mount. 



Simple Methods for Staining Liquid Blood.* — R. Ross describes 

 three methods for staining blood. 



1. Glass Rod Method : A large drop of blood is taken upon a slide 

 and a drop of stain not larger than the drop of blood is quickly placed 

 close beside it with the end of a glass rod. Then with the other end of 

 the rod the two drops are thoroughly mixed together, and small 

 quantities of the mixture (say of the size of a pin's head) are trans- 

 planted on to other slides, and each covered with a shp. Aqueous 

 solutions of many stains may be employed, and will not generally dissolve 

 the red corpuscles if the amount of solution used be not in excess of the 

 amount of blood. One of the most useful stains is an old polychrome 

 filtered saturated aqueous solution of methylen-blue in 0*5 p.c. salt 

 solution. 



2. Agar Method : Ordinary nutrient agar is melted and mixed with 

 filtered saturated solutions of various stains (e.g. polychrome methylen- 

 blue) and poured on sloped slides so as to obtain very thin films of the 

 stained agar on the glass. The agar sets at once, but does not dry for 

 some time. While still moist, a covershp charged with a droplet of blood 

 is placed on it. In a few minutes the elements absorb the stain from 

 the agar. The agar film should be very thin but deeply stained. 



8. Drained-drop Method : A cover-sHp is charged with a droplet of 

 blood shghtly spread out upon it, and is then inverted on a shallow 

 cell made with vaselin on a slide. The covershp is then pressed down 

 so that the blood-film is in contact with the surfaces of the slip and 

 slide. For staining, the blood may be mixed beforehand with a solution 

 of some stain or perhaps better with a few particles of the undissolved 

 stain. 



Ammonio-silver Method for Staining Cancerous Tissue.! — W. F. 

 Robertson and M. C. ^Y. Young communicate the following technique 

 of the ammonio-silver method with gold toning and cyanide decoloration. 

 Place thin sUces of tissue in Heidenhain's sublimate solution. After 

 from 12-24 hours, wash the pieces shortly in water and place them in 

 80 p.c. alcohol (made with absolute alcohol), to which iodin dissolved 

 in absolute alcohol has been added until the fluid has the colour of 

 pale sherry. Renew this fluid daily until it ceases to be decolorised 

 (generally from 4-6 days). Then place the tissues in 80 p.c. alcohol 



* Lancet, 1907, ii. pp. 219-20. t Tom. cit., pp. 358-61 (10 figs.). 



