INTERFRETATÏON OF ULTRAST‘RÜCTÜRE
139
These are primary loops. Samples to be frozen are‘placed on the fornivari To cOat the
sample With a coVering sheet, a copper wire loop, about 7—8 mm in diameter is made as
above, but the loop is cut open before coating it With thin
(svergold interferenoe
colors), so that the loop holding the sample may be passed through the split loop transfer- '
ring its thin formvar coat to the uneoveted side of the sample thus sandwiching it between
the formvar sheets. The sample is then frozenas described below.
"
Rat pancreas and
was obtainedfrom Nembutal anesthetized animals kept in a
moist chamber similar to that described by Gersh (1956). Air was pumpedthrough warm
water and into the chamber so that the atmosphere‘was saturatedwith water (asevidenced
by condensation on all viewing windows in the chamber). With the aid of a disSeCting
microscope, pieces of tissue from 01 mm to 0.5 mm maximum dimensions were removed
with ne forceps and iridectomy scissors, placed on the loops and" sandwiched in the
chamber, i.e., in a watersaturated atmosphere… They werethen frozen as describedbelow,
The entire operation from tissueremŒal to nal freezing took about 15 seconds after some
practice.
-,
.
,
…
-
f
;
'
Eggs were handled as in Allen, 1953 and Rebhun, 195955and _concentrated by. centrifu—
gation. They were then taken up in a 1 cc tuberculin syringè equipped with a 24 gauge needle.
'
Egg samples 0.005 to 0.01 m1 in volume were placed onÆthe formvar;loops and quickly
sandwiched, a process, which spreads the sample to-a layer one eggthiok,;i£., approxima—
tely 60 microns in thickness. This operation took less than threeseconds.
_
,
It should be noted that these techniquesexpose cells to dry air fora mm1mum length of
time (three seconds for Spisula, zero second for rat). ;
_
[_…î—
,
'
_
G. Sample Fræzing
…
;
ï.
7
“
Thermocouple measurements indicate the p0ssibity
coolmg m theÏvèrp0r
above the quenching uid if samples are not
1mmersed in the
reason
and because cooling under conditions of turbulence
more efcient
than under conditions of laminar ow,
u1dW1th a
retractable spear gun—like apparatus. The result is that “thç51œp Which‘containedïthe SPCcimen is immersed rapidly in the uid and the spear
it is ÏwithdraVïàbove the
liquid surface in less than_a twentieth of a Second.
'
_
__
H. Dehydraon Time
‘
.)
,
Dehydration’ of frozen samples was
2—3
Adiscuss1onofusaspectofthework
The results o-all‘this Work can again
eliminated«one Œ:thetwontypes of
pteVi0uSlÿ invaably
obtain—
ed—namély, the: one, whièh reSembledÈ Chemical xatwnThat1s, We nowài‘nvaably‘obtain—‘
ed morphology” similar tothat seen
er 2,a morphology
be
due to a crystaization phenomenonzcof Some sortHowever,thlswas dehiteprbgrèss‘ad
suggested an approach
namely c0ntr—‘ol—
ling water
of
eezig;Th‘e‘gmethodsf are
discussedîin*the ext
Paragraph.
’
-
«
»
139
These are primary loops. Samples to be frozen are‘placed on the fornivari To cOat the
sample With a coVering sheet, a copper wire loop, about 7—8 mm in diameter is made as
above, but the loop is cut open before coating it With thin
(svergold interferenoe
colors), so that the loop holding the sample may be passed through the split loop transfer- '
ring its thin formvar coat to the uneoveted side of the sample thus sandwiching it between
the formvar sheets. The sample is then frozenas described below.
"
Rat pancreas and
was obtainedfrom Nembutal anesthetized animals kept in a
moist chamber similar to that described by Gersh (1956). Air was pumpedthrough warm
water and into the chamber so that the atmosphere‘was saturatedwith water (asevidenced
by condensation on all viewing windows in the chamber). With the aid of a disSeCting
microscope, pieces of tissue from 01 mm to 0.5 mm maximum dimensions were removed
with ne forceps and iridectomy scissors, placed on the loops and" sandwiched in the
chamber, i.e., in a watersaturated atmosphere… They werethen frozen as describedbelow,
The entire operation from tissueremŒal to nal freezing took about 15 seconds after some
practice.
-,
.
,
…
-
f
;
'
Eggs were handled as in Allen, 1953 and Rebhun, 195955and _concentrated by. centrifu—
gation. They were then taken up in a 1 cc tuberculin syringè equipped with a 24 gauge needle.
'
Egg samples 0.005 to 0.01 m1 in volume were placed onÆthe formvar;loops and quickly
sandwiched, a process, which spreads the sample to-a layer one eggthiok,;i£., approxima—
tely 60 microns in thickness. This operation took less than threeseconds.
_
,
It should be noted that these techniquesexpose cells to dry air fora mm1mum length of
time (three seconds for Spisula, zero second for rat). ;
_
[_…î—
,
'
_
G. Sample Fræzing
…
;
ï.
7
“
Thermocouple measurements indicate the p0ssibity
coolmg m theÏvèrp0r
above the quenching uid if samples are not
1mmersed in the
reason
and because cooling under conditions of turbulence
more efcient
than under conditions of laminar ow,
u1dW1th a
retractable spear gun—like apparatus. The result is that “thç51œp Which‘containedïthe SPCcimen is immersed rapidly in the uid and the spear
it is ÏwithdraVïàbove the
liquid surface in less than_a twentieth of a Second.
'
_
__
H. Dehydraon Time
‘
.)
,
Dehydration’ of frozen samples was
2—3
Adiscuss1onofusaspectofthework
The results o-all‘this Work can again
eliminated«one Œ:thetwontypes of
pteVi0uSlÿ invaably
obtain—
ed—namély, the: one, whièh reSembledÈ Chemical xatwnThat1s, We nowài‘nvaably‘obtain—‘
ed morphology” similar tothat seen
er 2,a morphology
be
due to a crystaization phenomenonzcof Some sortHowever,thlswas dehiteprbgrèss‘ad
suggested an approach
namely c0ntr—‘ol—
ling water
of
eezig;Th‘e‘gmethodsf are
discussedîin*the ext
Paragraph.
’
-
«
»