116 SUMMARY OF CURRENT RESEARCHES RELATING 10 



ammoniacal solution of silver oxide. This was prepared by adding to 

 2 p.c. silver nitrate a few drops of 40 p.c. solution of sodium hydroxide, 

 and dissolving the precipitate with ammonium hydroxide. After a 

 period varying with the nature of the material, the pieces were washed, 

 and then transferred to 20 p.c. formalin. After 12 hours the prepara- 

 tion was dehydrated, cleared, imbedded in paraffin, sectioned, and mounted 

 in balsam in the usual way. The foregoing method was found to be 

 superior to all others, such as those of Golgi, Ramon y Cajal, Vom 

 Rath, etc. 



New Method of Staining the Connective-tissue Framework of 

 Viscera.* — D. Timofejew makes freehand or frozen sections of organs 

 of freshly killed animals, or of pieces which have been immersed in 

 physiological salt solution for one day. The sections are placed for 

 15 to 20 minutes in the following solution : — Methylen-blue (Ehrlich 

 rectified) 1 grm., physiological salt solution 2000-4000 c.cm. The 

 sections do not harm if left in the staining fluid for 24 hours. On 

 removal the sections are carefully washed in salt solution, and then 

 transferred for ^ to 1 hour, or even 24 hours, to a very weak solution 

 of ammonium picrate (0'1 grm. ammonium picrate in 800-1200 c.cm. 

 of physiological salt solution). The differentiation takes place in a few 

 minutes, and its progress may be watched under a low power. The 

 sections are mounted in the following fluid : — Saturated aqueous solution 

 of ammonium picrate 35 c.cm., glycerin 50 c.cm., and distilled water 

 50 c.cm. In case the nuclei are not sufficiently stained, the preparation 

 may be treated with Hoyer's picrocarmin. After-staining with Cajal's 

 mixture of indigo-carmin and picric acid stains the collagen green, the 

 other tissues remaining violet. A lengthy description of the appearances 

 in different organs is given. 



(4) Staining- and Injecting. 



New Method of Demonstrating the Spores in Acid-fast Bacteria. f 

 L. von Betegh makes use of a stain made up as follows : 2 grm. of pure 

 dahlia are dissolved in 20 grm. of 95 p.c. alcohol ; to this are added 

 50 grm. of distilled water and 4 or 5 drops of strong carbolic acid. 

 L. von Betegh's process consists of the following steps : Stain with warm 

 carbol-fuchsin as usual ; wash ; stain with dahlia two or three minutes 

 at room temperature ; wash ; stain with iodine solution (iodine 1 grm. 

 potassium iodide 2 grm. distilled water 100 c.cm.) 10 to 15 minutes ; wash 

 in alcohol-acetone until no more stain conies away ; wash ; counterstain 

 with picric acid or malachite-green ; wash ; dry, and mount. By this 

 method, the author shows that acid-fast bacilli contain spores which are 

 not acid-fast. He considers that some such method should be employed 

 in routine examinations for tubercle bacilli. 



Methods of Demonstrating the Flagella and Minute Structure of 

 Spirillum volutans4 — F. Fubrmann investigated living spirilla on a dark 

 ground, using Reichert's mirror-condenser. To keep spirilla at rest for 

 this mode of examination, he prepared a fine film of the thin bacterial 



* Anat. Anzeig., xxxv. (1909) pp. 295-301. 



t Centralbl. Bakt., lte Abt., lii. (1909) pp. 550-3. 



I Op. cit., 2te Abt., xxv. (1909) pp. 129-35. 



