138 Answers to Queries. 
spheeraphides, or crystal prisms, has not yet been discovered. 
Some consider them as aggregations of waste, a kind of excreta. 
That they do not strengthen the stem of the plant in which they 
are produced is evident, by the extremely brittle nature of those 
which furnish them in great quantity, such as the Cactus tribe. 
H. W. Lerr Via 
377.—Crystals are formed from the cell sap either in the cavity 
er wall of the cell. They consist of calcium phosphate, but 
generally of calcium oxalate, the latter salt being of two different 
forms. When the calcium oxalate crystallises with 6 equivalents 
of water, prisms and octohedra belonging to the dimetric system 
are formed ; when only with two equivalents of water, then in 
raphides or needle-like crystals, belonging to the monoclinic 
system. ‘The calcium oxalate is a secondary product of metastasis, 
the excess of calcium taken up from the soil being thus got rid of. 
The elements existing in the ash of plants are present only in 
very small quantities, but are essential to their lives. The sulphur 
is obtained from salts occurring in the soil, such as calcic sulphate, 
part of the lime being got rid of by the formation of crystals of 
calcic oxalate in the cells of diciduous and other parts of plants. 
V. ASE. 
378.—Bleaching Skeleton.—By well soaking in benzine and 
then in water in the sun, or by burying in white shore sand in the 
sun, or place in the oven till well heated. A solution of chloride 
of lime may be used also. ‘Try steeping a little cotton wool ina 
liquid made of equal parts of water and alcohol, and rubbing 
some on the bones. If not sufficient then try with a solution of 1 
part of chloride of lime in 4 parts of water. V. ALE: 
380.—Freezing Microtome. —Sections of ovaries, petals, thin 
leaves, and slender stems, such as those of mosses, can be most 
advantageously made by means of a Freezing Microtome. I use 
one of Cathcart’s for the purpose and find it all that could be 
desired. H. W.. Levey ie 
381.—Queen Bee.—I have been a bee-keeper for close on forty 
years, and every summer handle many Queen Bees, sometimes 
holding them in my lips for a few seconds while my hands are 
busy, and I have never been stung by one. There is not the least 
doubt that her winged majesty can sting, for it is by the use of her 
sting she gets rid of arival. The sting of the Queen differs from 
that of the worker bees in being slightly curved, the weapon of 
the latter being quite straight. H. W. Lett, M.A, 
382.—Plant Hair.—It will be noticed that generally speaking 
plant hairs are more frequently found on the under than on the 
upper surface of the leaf. When the leaf is young and tender, it 
