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SUMMARY OF CURRENT RESEARCHES RELATING TO 
preserved in bottles with ground glass stoppers, and the author uses it 
chiefly for mucosae and embryonic tissues. Number 2 is made with 
Extractum alkannae (Orcanette). 1 grm. of this is dissolved in 3 grm. 
of turpentine oil, and after filtration through linen 10 grm. of sulphuric 
ether are added. One objection to this mixture is its liability to pass 
through the walls of lymphatics and stain the fat. The basis of Number 3 
is known commercially as absolute black. Of this 5 grm. are rubbed up 
for 10 minutes with 5 grm. of unboiled linseed oil in a porcelain mortar, 
and then 10 grm. of turpentine essence and 10-15 grm. of sulphuric 
ether are added. The mixture is filtered and preserved in glass-stoppered 
bottles ; it must be well shaken each time before being used. Number 4 
has a red colour, and is more difficult to make and to preserve. 5 grm. 
of very finely powdered cinnabar are rubbed up with 15-20 drops of 
unboiled linseed oil in a warmed porcelain mortar until a thin paste is 
formed (10-15 minutes). This is then mixed with 3 grm. of turpentine 
oil and 5 grm. of chloroform, after which it is filtered and preserved as 
before. This injection should always be prepared in small quantity, and 
used while quite fresh. 
In injecting these coloured fluids special attention is paid to the 
syringe, which should be cleaned from time to time with turpentine and 
ether, since the leather plug is apt to give off a little dust. The syringe 
used by the author is much like an ordinary syringe used for injecting 
therapeutic remedies, but is easily taken to pieces, and therefore easily 
cleaned.. The only material difference is that the needle is made of 
glass drawn out to a fine point. Many of these glass needles are necessary 
for working the syringe quickly. 
Staining Mucus. * — Dr. Paul Mayer discusses the various reagents 
used for staining mucus. He begins with “ the so-called hematoxylins.” 
Hematoxylin alone does not stain nuclei or mucus ; the presence of an 
inorganic salt is necessary, and then it is not unchanged hematoxylin 
but its oxidation stage — hematein — which forms the stain. It is, there- 
fore, more exact to speak of “ hsematein-Tlionerde,” “ kemalum,” “ hema- 
calcium,” &c. The indispensable “ ripening ” of hematoxylin solutions 
depends not merely on an oxidation to hematein, but also on a gradual 
weakening of the originally acid reaction of the alum. For rapid and 
intense mucus staining, Mayer recommends “ muchaematein,” with the 
following composition : — hematein • 2 grm., aluminium chloride * 1 grm., 
glycerin 40 ccm., distilled water 60 ccm., or leaving out the glycerin 
and water, an alcoholic solution may be made with 100 ccm. of 70 per 
cent, alcohol and 1-2 drops of nitric acid. 
The author goes on to discuss metliyl-green, iodine-green, methylen- 
blue, methyl-violet, thionin- and toluidin-blue, bismarck-brown, and 
safranin. Thionin is equalled or surpassed by mucicarmin, the receipt 
for which is as follows : — Carmine 1 grm., aluminium chloride *5 grm., 
distilled water 2 ccm., heated over a small flame for about two minutes 
until the mixture is quite dark. Then 100 ccm. of 50 per cent, alcohol 
are added. For most cases, to stain the mucus only, the solution should 
be diluted to 1/5 to 1/10 with alcohol, or to 1/10 with water. Instead 
of fixing the paraffin sections on the slide through a medium of water 
* MT. Zool. Stat Nenpel, xii. (1896) pp. 803-30. 
