"AYA 
POSE 
VES 
CONDUCTED BY F. SHILLINGTON SCALES, F.R.M.S. 
PREPARING AND MOUNTING WOOD SECTIONS.—- 
Mr. J. D. King in a recent paper in the “Journal of 
Applied Microscopy” gives a very practical exposi- 
tion of his methods of preparing and mounting wood 
sections. He lays stress upon the necessity of 
using a good knife of the finest steel and the finest 
edge, as well as a thoroughly satisfactory microtome. 
We have found the ordinary English section-knife or 
razor barely strong enough for this purpose, and a 
properly sharpened plane-iron is preferable. For 
embedding, hard paraffin should be used, as it shrinks 
less and holds the object more firmly. It will 
probably roll, but a light pressure with the ball of the 
finger when cutting will remedy this. The thickness 
of the sections is a matter of some importance, and 
the general tendency is to cut them too thin. If 
transparency is required, the sections must be bleached, 
and this requires care, as over-bleaching destroys the 
fibres of the section, and under-bleaching leaves a 
blotchy appearance. Mr. King suggests bleaching 
until the colour is discharged from the wood, but no 
longer, and then a very thorough washing with water. 
In this connection we think an ‘‘anti-chlor” such as 
hypo-sulphite of soda might be used with advantage, 
but in any case the final washing must not be 
curtailed. The stains recommended are Delafield’s 
haematoxylin, Bismarck brown, and for double 
staining, Grenachers borax carmine and methyl or 
aniline green. The haematoxylin is the most gener- 
ally useful, but is commonly made in too strong a 
solution. It is best to stain slowly in a comparatively 
weak solution, and when using this reagent itis a good 
plan to wash finally in hard water from a tap, which has 
a tendency to fix the colour. The Bismarck brown 
is useful for very delicate structure, or for large spiral 
or scalariform vessels. The double staining is best 
carried out by immersing the section in borax carmine 
for twelve hours or more, washing quickly, but well, 
in 50 per cent. alcohol, placing for two or three 
seconds only in aniline or methyl green, washing as 
before, and then again staining in borax carmine till 
the red reappears, changing the supply of stain after 
the superfluous green is driven out. Mr. King 
recommends finally mordanting the section in alum 
cochineal. He gives the needed warning that 95 per 
cent. alcohol will precipitate borax carmine, and 
that alcohol and haematoxylin must be kept separate. 
He recommends that glycerine jelly be used as a 
mounting medium, but Farrant’s solution, or Canada 
Balsam will give satisfactory results. The great 
difficulty will lie in getting rid of air-bubbles, especially 
“stowaways,” and these must be carefully worked 
out with a dissecting needle under a dissecting micro- 
scope. 
DENDRITIC CRYSTALS IN PAPER.—Several corres- 
pondents have been good enough to send us specimens 
of these, as requested in last month’s SCIENCE-GossIP. 
Will any of our readers who have observed such 
crystals in papers other than blue tinted papers, kindly 
send us particulars, and if possible some of the 
examples for examination, which can be returned. 
SCIENCE-GOS STP. 
Locust DisEAs— FuNGus.—Reports in the Jgv7- 
cultural Journal, published by the Cape Department 
of Agriculture, give most interesting accounts of the 
success attained in many districts in the extermina- 
tion of locusts by means of the locust disease fungus. 
The fungus is prepared by the Bacteriological Insti- 
tute, Grahamstown, and any applicant can obtain a 
tube for the sun: of sixpence. The reports show that 
in one case about a hundred locusts inoculated with 
the disease were distributed amongst a swarm, and 
next morning and within a few days after, large 
numbers of locusts were lying dead amongst the sand- 
dunes. The microscopical examination and subse- 
quent experiments showed that they were unques- 
tionably killed by the fungus. The growth of 
fungus from the dead locusts produced a fungus 
smaller in size, but more rapid in its growth, than the 
Government fungus. In another case young locusts 
were immersed in lukewarm water, in which the 
fungus had been mixed, and then set free. Three 
days afterwards rain fell, and on the fourth day small 
heaps of locusts were found about three miles away 
from where they had been immersed. Other districts 
in which no such means of inoculation were carried 
out were found to be much more infested with locusts. 
We shall await further reports with interest.—/. 
Shillington Scales. 
NOMENCLATURE OF NUMMULITES PERFORATA.— 
I have received a note from Mr. Fortescue W. Millett, 
the eminent authority on Foraminifera, with regard to 
the nomenclature of Mzmmulites perforata, which 
will be interesting to your readers studying these 
forms. He says:—‘‘I have seen your paper in 
SCIENCE-GossIP on the forams of the Tocha Valley. 
LV. perforata was not so named for the reason you 
suggest (ante, p. 165). The rude figure of Zgcon 
perforatus being the xlii. genre of Montfort’s Conch. 
Syst. 808, p. 167, is either a copy, or an imitation of 
Fichlel and Moll’s figure of Mazdtelus lenticulards 
var. Test. Micr. 1798, p. 57, pl. vil. fig. h. 
It represents a shell with sinuous striae, between 
which are tubercules or perforations, hence Montfort’s 
name.”—Arthur Earland, 28, Glenwood Road, 
Catford. 
- 
ANSWERS TO CORRESPONDENTS. 
Narps.—V. T. (Chorley.)—The annelids you send 
are Naids—WVats proboscidea ; so called from its long 
and contractile prostomium. It is common amongst 
Lemnae, and its wonderful transparency makes it a 
most interesting microscopic object when living. The 
contractions and dilations of the vascular trunk can be 
easily observed, as also the constant movement of the 
prostomium, which though contractile. is not retractile. 
During the summer months the Naids frequently 
reproduce themselves by fission, a new individual 
being formed by constriction at one of the segments. 
Hrratic.—J. T. (Streatham).—Mr. W. West, of 
3radford, has kindly identified your Hepatic, as 
Lejeunta serpyllifolia, a plant which varies much as 
to locality. 
MOUNTING BOTANICAL SLIDES.—J. R. (Rapallo, 
Italy.)—The best book for the beginner is Cross and 
Cole’s ‘* Modern Microscopy.” Pages 114 and 144 to 
154 deal specifically with the mounting of botanical 
specimens and are most clear and lucid, as might be 
expected from a mounter of Mr. Cole’s experience. 
I would also recommend strongly to your notice 
Strasburger and  Hillhouse’s ‘* Practical Botany” 
which, written primarily for the student of botany, 
contains eminently practical instructions in micro- 
scopical technique, and should be mastered by all who 
are interested in plant life. 
