276 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Fixing and Staining the Nuclei and Spores of Yeast.* — Herr H. 
Moeller, after trying many fixatives for yeast preparations, such as 1 per 
cent, iodo-potassic iodide, absolute alcohol, boiling in amyl-alcohol, and 
boiling in glycerin, finds that boiling for 1 to 2 minutes in distilled water 
succeeds best. The author has given up gentian-violet and taken to 
Heidenhain’s method, which consists in treating the fixed cover-glass 
preparations with ammonium ferric sulphate [(NH 4 ) 2 Fe 2 (S0 4 ) 4 ]. In 
a 3 or 4 per cent, solution of this ammonia-iron fluid the preparations 
are immersed for two hours at least. They are next washed in water 
and then stained for half an hour in a saturated aqueous solution of pure 
hrematoxylin. After removal the preparations are again washed in water 
and then differentiated in the iron solution (1/2 to 2 minutes). This last 
procedure should be watched under the Microscope. 
Staining Spores, j — Dr. P. Jaisohn recommends the following modi- 
fication of Moller’s method. After preparing a slide so that a drop of 
water spreads evenly on the surface, he gently passes a needle that has 
touched a recent culture a few times through the water. The slip must 
then be kept in a thermostat at 35° to 38° till the water is entirely 
evaporated ; the slide is then passed three times through a flame, and 
placed in 5 per cent, chromic acid for two minutes, washed in water, and 
placed for three minutes in a solution of 3*5 grm. fuchsin, 35 ccm. 
absolute, 13 grm. phenol, and 230 ccm. water. After the superfluous 
stain is washed off, put in Loeffler’s solution for two minutes ; wash and 
mount. The bacteria will stain blue and the spores red. 
Selective Power of Cells in the Absorption of Pigments.^ — Herr 
L. Lilienfeld states that nuclein acids derived from various sources take 
up the same pigment as the framework of the nucleus, while pure 
albuminoids behave in the same way as the cell-protoplasm. The 
nuclein-substances of the nucleus always take up the basic, while the 
albuminoids of the cell-body absorb the acid pigment out of a mixture. 
If a blue basic and a red acid pigment are mixed, the framework of the 
nucleus assumes a blue, the cell-protoplasm a red colour. The staining 
of nuclein-acids by basic pigments suggests the formation of a salt. 
Staining Tubercle Bacilli in Sublimate Solutions of Anilin Dyes.§ 
— Drs. Nastiukow and Pewsner have devised the following method for 
staining tubercle bacilli. A 1 : 2000 solution of sublimate is mixed with 
anilin oil and then filtered. Of this 10 ccm. are mixed with 1 ccm. of a 
10 per cent, alcoholic solution of gentian-violet, methyl-violet or fuchsin, 
and in this solution the preparations are immersed for five minutes. 
After having been washed in distilled water they are completely de- 
colorized in dilute hydrochloric acid. The preparation may be contrast- 
stained in one per thousand solution of malachite-green, or one per two 
thousand of eosin in sublimate. Preparations thus stained need not be 
fixed in the flame, nor need the staining fluid be warmed. 
* Centralbl. f. Bakteriol. u. Parasitenk., xiv. (1893) pp. 358-60. 
t Amer. Mon. Micr. Journ., xiv. (1893) pp. 321 and 2. 
X Yerhandl. Phys. Gesell. Berlin, 1893, No. 2. See Bot. Ztg., li. (1893) 
2 ,c Abtheil., p. 297. 
§ Wratsch, 1893, No. 3. See Centralbl. f. Bakteriol. u. Parasitenk., xiv. (1893) 
p. 816 . 
