ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
565 
appears might be due to the presence of living forments he prepared a 
solution of the following composition : — Distilled water 200 ccm. ; potash 
or ammonia alum 7J grm.; chloral hydrate 4 grm. ; haematoxylin 
crystals 1/10 grm. This aqueous solution had, at the time of writing, 
been treated for nearly a year, and there was not then any deposit, while 
the action of the stain was as good as at first. In preparing the solution 
the water and alum should be boiled in an agate or porcelain vessel for 
from 5 to 20 minutes, to destroy any germs in the water or alum. 
As haematoxylin is almost a pure nuclear dye it is recommended that a 
counter stain be used with it ; eosin is very good, and for many objects 
picric acid is suitable. 
Ruthenium-red as a Staining Reagent.* — M. L. Mangin recom- 
mends the use of the ammoniacal oxychloride of ruthenium or ruthenium- 
red discovered by M. Joly, as a staining reagent for vegetable tissues. 
It is soluble in water, concentrated calcium chloride, and solution of 
alum ; insoluble in glycerin, alcohol, and essence of cloves. It belongs 
to the group of basic pigments, inert to cellulose and callose, but taken 
up eagerly by pectic substances. It is, in fact, the best staining reagent 
for the analysis of vegetable membranes ; the staining resisting power- 
fully the influence of alcohol and glycerin. It is also permanently fixed 
by gums and mucilages derived from pectic compounds, but does not 
stain muc lages derived from cellulose, or from the products of the 
liquefaction of callose. Illustrations of these reactions are given in the 
cases of various tissues and organs. 
Staining Properties of Oxychloride of Ammoniacal Ruthenium, f — 
The staining properties of this substance, the formula for which is Bu 2 
(OH) 2 Cl 4 (A 5 H 3 ) 7 -j- 3H 2 0 have been examined by MM. M. Nicolle 
and J. Cantazucene. It exists as brownish crystals, and is soluble in 
water and glycerin, but not in alcohol. It appears to be easily acted on 
by acids and alkalies. The authors used an aqueous 1 per thousand 
solution in which the sections were immersed for one to two minutes, 
after which they were dehydrated and mounted in balsam. It imparts 
a beautiful red hue and has special affinity for the nuclear chromatin. 
It may be used after most fixatives, and while it is stated to give brilliant 
results after osmic acid, it is inert after Flemming’s solution or after 
osmic acid plus bichromate. Its potentialities are not confined to sec- 
tions as it stains cover-glass preparations and all micro-organisms, 
except the tubercle and leprosy bacilli. Its chief merits seem to be that 
it picks out the nuclear chromatin very well, and that it is insoluble in 
alcohol. 
A new Staining Method for Neuroglia.^ — Prof. N. Kultschitzky 
has discovered in Patentsaures Bubin, prepared by the “ Berliner Anilin- 
farben-Actiengesellschaft,” a very successful stain for neuroglia, which 
renders the cells and the fibres a beautiful red-violet colour. 
For fixing and hardening, the following mixture is used : — 50 per 
cent, methylated spirit, plus so much bichromate of potassium and 
sulphate of copper as will dissolve in the spirit to which 1/2 to 1 per cent. 
* Comptes Kendus, cxvi. (1893) pp. 653-6. 
t Ann. Inst. Pasteur, vii. (1893) pp. 331-4. 
X Anat. Anzeig., viii. (1893) pp. 357-61. 
