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-arrange diatoms and pursue similar min 
_ Sharply pointed feathers on the extreme en 
MICROSCOPY. 697 
when silica is precipitated from its alkaline salts or water-glasses 
dissolved in water; but a mixture of glycerine retards the pro- 
cess and gives opportunity for the formation of definite forms. 
The films thus produced, washed and examined in water or 
mounted in balsam, either simulate organic cell forms, with cavi- 
ties formed by the bursting of minute gas-bubbles, or consist of 
beads or spherules exhibiting remarkable regularity of size and 
arrangement; the beads seem to vary from zyġov tO roo000 inch 
or less; and they appear to least advantage, in size, under the 
highest powers. They seem calculated to add to our knowledge 
of high power definition if not to throw light upon questions of 
crystallization and organization. Some of the films produced the 
beautiful polychromatic effects so often mentioned by Dr. Pigott 
as occurring in beaded diatoms and scales. $ 
CELL-CULTURE IN THE Srupy or Funer.—Ph. Van. Tieghem 
and G. LeMonnier in their published researches on the Mucorini 
give a good working account of their method of cell-culture which 
is applicable not only to the smaller fungi but jo many other 
plants. A glass cell 1 or 4 inch is cemented upon a glass slide, 
and a suitable cover-glass is kept in place by three minute drops 
of oil placed on the edge of the ring. The contained air is kept 
moist by a few drops of water placed in the bottom of the cell, 
while a very small drop of the nutritive fluid is placed on the 
lower surface of the cover-glass, and in this drop the spore to be 
cultivated is sown. The whole drop, and indeed the entire con- 
tents of the cell, can now be examined with suitable powers, and 
the germination and development of the plant traced hour after 
hour from any given spore, with the greatest certainty and ease. 
Extraneous spores will sometimes be introduced, but they are 
easily detected. 
Hanpiixne Diatoms. — Capt. Lang, of the Reading Microscop- 
ical Society, gives “ A useful Hint ” to persons who select and 
ute work under the micro- 
Scope. Hairs, from various animals, whipped on to delicate 
handles, are generally satisfactory, those of T, or fine 
camel-hair or sable brushes, being generally useful. But some 
diatoms refuse to be thus picked up, and these he finds to be read- 
ily handled by means of a fine feather. ‘The fine, stiff, elastic, and 
d of the carpal joints 
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