134 Answers to Queries. 
chromic acid for fourteen days. Then add a few drops of hydro- 
chloric acid to the fluid to soften the bone. The bone around the 
labyrinth is very dense, and requires a longer time than the other 
parts to become soft. Wash thoroughly for 12 hours in water ; 
place for 36 hours in syrup and 48 hours in gum; then freeze 
in gum in a freezing microtome. (See also Dr. Urban Pritchard’s 
method.) V, Ale 
355.—Starches.—Breathe on the slide, and when it has evapo- 
rated it is not advisable at once to drop on the dammar, but, first 
placing over the starch a clean cover-glass, put at each edge of the 
cover, but not exactly opposite, a drop of dammar, which, running 
under the cover from each side, will imprison the object. If the 
dammar wave does not appear to travel freely, a little movement 
with a needle at the edge not touched by the medium will accom- 
plish the purpose, and the slide may then be put away to dry, but, 
in this case, it is not well to put the starches in a warm place. It 
is a good way for mounting pollens, fern-spores, etc. This is 
mostly for polariscope. For ordinary mounting, Farrant or glyce- 
rine is recommended. (See Science Gossif, 1881, pp. 88—135 
and 160.) VIA 
359.—Thorax.—Full instructions will be found in Zhe Journal 
of Microscopy and Natural Science, Vol. 2, October, 1883, under 
the head of Microscopical Research in the Zoological Station at 
Naples, but if “ Histo.” cannot obtain this, the operations may be 
briefly summed up as follows :—Harden in successive strengths of 
alcohol, 10, 20, 30, 40, &c., per cent, ending with absolute alcohol. 
I find that everything depends on this being really absolute and 
not one or two per cent. below. Each stage to take 12 hours or 
longer. Next place in oil of cloves ; then in oil of cloves contain- 
ing a little soft paraffin; next keep warm in a drop of soft paraffin, 
melting point 40° C. forsome hours. Temperature must not rise 
higher than 45° on any account. Allow to cool, imbed in hard par- 
affin, and cut. Stain ifrequisite and mount in fluid balsam. J. W.G. 
367.—Sun putting out the Fire—If Captain Cuttle will 
perform a few simple experiments, with his usual cuteness, he will 
soon find that sun alone will not put out the fire, but that sun and 
neglect will do so. If the sun shines into a fire, the latter is 
apparently much diminished in intensity, but only on account of 
the comparatively feeble light from the fire being masked by the 
more inteuse light of the sun. The flame is there still, and the 
fire is there although it cannot be seen. Two things are necessary 
in order to have a fire; first, a supply of fuel ; second, a supply 
of oxygen at a sufficiently high temperature. 
When the sun shines in a room the fireis generally neglected, 
and by the accumulation of ashes over the fuel proper, combustion 
