SERIAL SECTION MOUNTING

14,il alcohol if it be desired to stain, or the sections may be
a'Ptzt i mounted from it direct in balsam.
t4      A simple modification (see below, No. 270) adapts the pro-
'4 o;6o cess to the case of celloidin objects.
flopi.  The methods of Schdillibaum and Mayer possess almost all
onot the advantages of the Frenzel-Threlfall method, and are some-
iyeess what more convenient in practice. The Frenzel-Threlfall
life ws method has the peculiarity of offering a dry film, on which
Attend  wrinkles may be smoothed out from large sections by brush-
Ere toe  ing with alcohol, which cannot be well done on a sticky film;
R tie  this is an advantage for such objects. But for small sections
Zaid  that are not likely to require smoothing a sticky film  is pre-
ler the  ferable, as it removes the risk of light sections being blown
dielQs: off the slide by a sudden draught, or by the breath of the
ldlille : operator, as sometimes happens.
a1f    266. Shellac     Process   for  Section-fixing  (Giesbrecht's
method ').-Prepare a stock of slides covered with a thin and
elego  even film of shellac. This is done as follows : Make a not too
a strong solution of brown shellac in absolute alcohol, filter it
isol.  thoroughly; warm the slides, and spread over them a layer of
hootihy  shellac by means of a glass rod dipped in the solution and
Puttle  drawn once over each slide. Let the slides dry.
isth    Just before beginning to cut your sections take a prepared
has  slide and brush it over very thinly with kreasote applied by
otas  means of a brush; this forms a sticky surface on which the
wto  sections are now arranged one by one as cut, care being taken
u  to bring them  on to the slide with as little surrounding
jat  paraffin as possible.
g   When all the sections are arranged the slide is heated on a
StI    water-bath for about a quarter of an hour at the melting
vervof point of the paraffin; this causes the paraffin to run down
into a thin layer, and allows the sections to fall through it
Act  and come into close contact with the shellac film, whilst at the
Sew. same time it evaporates the kreasote.
I I Zool. Anz.,' No. 92 (vol. iv, 1881), p. 484.

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