ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
249 
which all the apparatus required consists of (a) a sterilised lancet-shaped 
needle ; (b) the small pipette in which the blood has been collected, and 
of such diameter that after it has been broken across (the platinum loop, 
which is used for measuring the serum, can easily be introduced into it 
if necessary) ; (c) a platinum loop, measuring about 1 mm. in diameter, 
and holding about 1 mgrm. of fluid ; (d) slide and cover-glass ; (e) a tube- 
culture of the typhoid bacillus in neutral bouillon. The culture should 
not be more than 24 hours old, should be free from clumps, and the 
bacillus actively motile. The procedure is as follows : — With the 
sterilised loop nine drops of the culture are deposited separately on slide 
or cover-glass. One drop of blood is then added, and the 10 drops 
thoroughly mixed together. The phenomena observed differ according 
to whether the serum is potent or not. If the serum be potent, all 
the bacilli will be agglomerated in from five to thirty minutes ; if feeble, 
the clumps form gradually, but positive diagnosis can be made in from 
about a half to two hours. For further information and details the 
original should be consulted. 
(2) Preparing- Objects. 
Preparing and Staining Celery for Demonstrating Bacteria.* — Dr. 
TJ. Brizi hardened the diseased parts for 48 hours in a liquid composed 
of 100 parts of water, to which were added 1 part of glacial acetic acid 
and 1 part of chromic acid. The pieces were further hardened in 75 per 
cent., and then in absolute alcohol. The sections were cut by the par- 
affin method, and after the paraffin had been removed by means of chloro- 
form, were washed in warm water and then immersed in an aqueous 1 per 
cent, solution of methyl-green for three or four hours, after which they 
were treated with water acidulated with hydrochloric acid. In this way 
-everything but the bacteria was decolorised, and then the sections were 
contrast-stained in an aqueous solution of picrocarmin, in which they 
were allowed to remain for about an hour. The sections, having been 
washed and dehydrated, were mounted in balsam. Another good stain 
was gentian-violet and acetic acid (water 100, acetic acid 10, saturated 
alcoholic solution of gentian-violet 20). The sections were treated with 
this solution for about an hour, and then placed in strong spirit to which 
a few drops of hypochlorite of soda were added. By this procedure the 
tissue was quite decolorised, the bacteria being stained violet. 
Microchemical Methods for Examining Cells.j — According to Prof. 
.E. Zacharias, a mixture of methylen-blue and fuchsin S maybe used with 
great advantage to study the distribution of nuclein in the cell. If 
tissues of different origin are treated with dilute hydrochloric acid, and 
this mixture afterwards added, the constituents of the cell which contain 
nuclein are stained a deep blue, the parts without that substance being 
red. Sperm-cells of the Rhine-salmon were treated with dilute hydro- 
chloric acid to remove protannin, and then stained with the above 
mixture. Instantly the envelopes of the heads which contain the nucleic 
acid were beautifully stained bright blue ; the inner part of the heads 
seemed to be colourless ; the tails were stained red. Similarly treated, 
1897 
* Atti R. Accad. Lincei, vi. (1897) pp. 229-34. 
t Rep. 66th Meeting Brit. Ass., 1896, p. 1022. 
S 
