228 THE AMERICAN MONTHLY [ December, 
in the spirit and rub up the crystals with it in a glass mortar; add the spirit 
gradually till they are dissolved ; then add the water slowly, while stirring, 
and keep in a stoppered bottle. (2.) Make a saturated solution of chrysoidin 
in distilled water, and add a crystal of thymol to make it keep. (3.) Make 
a dilute solution of commercial nitric acid, one part of acid to two of distilled 
water. Spread a thin layer of sputum on a cover-glass and let it dry; when 
quite dry pass it two or three times through the flame of a small Bunsen 
burner, and let it cool. Filter two or three drops of the magenta solution 
in a watch-glass; place the cover-glass, with the sputum downwards, on the 
stain, taking care that there are no air-bubbles under it. Let it. remain for 
fifteen or twenty minutes; then wash in the dilute acid till all color has dis- 
appeared. Remove the acid with distilled water ; then place the cover-glass, 
in the same manner as before, on a few drops of chrysoidin filtered into the 
bottom of a watch-glass, and let it remain for a few minutes, till it has taken 
a dark brown stain. Wash off the superfluous color in distilled water, and 
place the cover-glass in absolute alcohol for a few minutes. Then remove 
and dry perfectly in the air, and mount in a solution of balsam. The bacilli 
are visible with a quarter-inch objective. By this means only A. tudbercu- 
os’s is stained, the ordinary putrefactive bacteria remaining colorless.’ 
The following is Heneage Gibbes’s rapid method of demonstrating B. ¢ader- 
calosts without nitric acid :— 
‘ Take of rosaniline hydrochloride 2 grms., methyl-blue 1 grm. ; rub up in 
a glass mortar. Then dissolve anilin oil 3 ccm., in rectified spirit 15 ccm. 
Add the spirit slowly to the stain till all is dissolved; then slowly add dis- 
tilled water 15 ccm., and keep in a stoppered bottle. Place a few drops of 
the stain in a test-tube and warm; as soon as steam rises pour it into a watch- 
glass, and place the cover-glass as before. After four or five minutes wash 
‘in methylated spirit till no more color comes away; drain thoroughly and 
dry, either in the air or over a spirit lamp. Mount in Canada balsam. A 
section of tissue containing bacilli can be treated in the same way, only it 
must be left in the stain for several hours. 
‘If gentian-violet be used after the nitric acid treatment, the putrefactive 
bacteria will be stained, and not the tubercle bacilli, which are thus strongly 
differentiated. The latter are also stained by fuchsin.’ 
—Oo—— 
Use of the cell nucleus.—An interesting experiment performed by Herr 
G. Klebs, an account of which is published in the ‘ Biologische Centralblatt,’ ’ 
seems to throw light on this subject. The cells of Zygnema, a common fresh 
water alga, were plasmolyzed by immersion in a 16 per cent. aqueous solu- 
tion of sugar, which strongly contracts the protoplasm without destroying its 
life. Asa result of the contraction the cell contents were observed to divide 
into two portions, each containing one of the two chlorophyll bodies, while 
the nucleus was not divided but remained in one of the halves. This division 
appears to be purely a mechanical process, the result of the plasmolysis. 
The plasmolyzed cells were cultivated and it was found that the two portions 
behaved very differently, the one which contained the nucleus soon formed for 
itself a new cell wall, the single chlorophyll body divided into two, and the half 
cell soon became a complete normal cell. Not so, however, with the half 
cells which did not contain nuclei. These retained their vitality for many 
days and produced starch abundantly, but had no power to form for them- 
selves a cell wall or to increase in length. The nucleus, therefore, seems to 
be necessary both to the increase in the length of the cell and to the formation 
of the cell wall.— West. Druggist. 
