786 SUMMARY OF CURRENT RESEARCHES RELATING TO 



organ is then suitably sliced with a sharp razor, and the slices are 

 transferred to glass dishes for staining. The bottom of these dishes is 

 covered with two or three layers of filter paper. The stain is prepared 

 as a stock solution of 1 grin, of Grii bier's methylen-blue in 200 c.cm. of a 

 saline fluid, and from this suitable dilutions are made. For nervous 

 tissues, 2 J T or ^ P- c - solutions are used. The warmed stain is poured over 

 the material from a pipette, and staining proceeds at a temperature of 

 37° C. At intervals the material is examined, to see whether the process 

 has gone far enough. As fixing fluid, a solution is used which contains 

 8 grm. of ammonium molybdate, and 0'5 c.cm. of formalin in 100 c.cm. 

 of distilled water. The material is transferred to this fluid, suitably 

 warmed, and left for 24 hours. Then it is well washed in warm water, 

 dehydrated in alcohols, cleared in oil of bergamot and xylol, and finally 

 mounted in damar-xylol. 



Preparation of Ammoniacal Silver Solution.* — A. Schlenmer 

 describes an improved method for the preparation of this fluid, which 

 is used in Bielschowsky's process for demonstrating connective-tissue 

 fibres in bone, dentine, and elsewhere. To a 10 p.c. solution of silver 

 nitrate is added 40 p.c. sodium hydrate in excess, and the precipitate 

 which forms is washed free of alkali. This precipitate is then dissolved 

 in as little ammonia as possible, and the solution is filtered through glass 

 wool. This solution is diluted with 9 parts of water, and is then ready 

 for use. 



Toluidin-blue.t • — L. Martinotti calls attention to a solution of 

 toluidin-blue with which he has got results as good as those obtained 

 with polychrome-blue. It has the following composition : — Toluidin- 

 blue 1 grm., lithium carbonate 05 grm., distilled water 75 grm., 

 glycerin 20 grm., alcohol (95 p.c.) 5 grm. The first two ingredients 

 are dissolved completely in the water, before adding glycerin and alcohol. 

 The method of staining is precisely the same as with polychrome-blue. 

 The solution is readily prepared. 



Hsematin Stains.J — L. Martinotti gives three formula? for haematin 

 solutions, of which the first two are based respectively upon Delafield's 

 and Unna's hematoxylins. They contain o^-O'S p.c. of haematin, 

 and varying proportions of methyl-alcohol, alum, glycerin, and hydrogen 

 peroxide. The results are constant and satisfactory ; the solutions are 

 easily prepared, and keep well. 



Chemistry of Vegetable Pigments. § — L. E. Cavazza gives an 

 account of his microchemical researches upon the colouring matters of 

 certain flowers, fruits and leaves. He classifies these substances into 

 fifteen groups, and gives in tabular form the effects of certain chemical 

 reagents upon the members of the different groups. 



New Dahlia Stain. || — Ballenger describes a new stain for motile 

 organisms, renal tube casts, and fixed smears of Spirochseta pallida. 



* Zeitschr. wiss. Mikrosk., xxvii. pp. 22-3. 



t Tom. cit, pp. 24-9. J Tom. cit.. pp. 30-3. 



§ Tom. cit., pp. 34-40. 



Ii Centralbl. Bakt., lte Abt. Ref., xlvii. (1910) p. 407. 





