76
A . M O S C O N A , O . A . T R O W E L L A N D E . N. W I L L M E R
certain amino acids and vitamins (Wolff, Haffen, Kieny and Wolff,
1953). These and similar methods have been used in the laboratories
of Spratt and of Wolff for the culture of whole embryos and parts
thereof and also for the growth of a variety of embryonic organ
rudiments (see Chapter 15).
Trowell (1952) cultured mature organs on a medium of serum-agar,
the final agar concentration being l-3°/o. The medium was contained
in a small glass cup which was enclosed in a sealed Perspex (Lucite)
chamber filled with oxygen.
A difficulty arises when thin sheets of material such as skin, diaphragm or mesentery are cultured on agar or on a plasma clot. Instead
of staying extended, the tissue tends to roll up into a ball because it
cannot adhere to the slippery surface. The difficulty can be overcome
by first laying a piece of lens paper or rayon fabric on the agar or
plasma clot, but it is easier to use other methods employing lens paper
or rayon, which will be described in the next section. Lens paper is a
very thin open-texture paper supplied for cleaning microscope lenses.
When embryonic organ fragments are cultivated they become encapsulated by a migration of cells from certain parts of the cut surface. This
leads to some reorganization of the organotypic structure which may
be undesirable. Wolff (1960) has found that this encapsulation can
be prevented if the culture is wrapped in vitelline membrane (from
hen's egg) before it is planted on the agar.
From the point of view of the survival of the culture, these agar
methods are quite satisfactory; indeed, the results have not been
bettered by any of the later methods, but there remains the technical
difficulty that the medium cannot be changed, added to or analysed
without transplanting the cultures. There was still the need to devise
a method in which the medium was fluid and readily interchangeable,
and the various ways of doing this will now be described.
E. O R G A N S ON A FLUID MEDIUM
1. "Sponge" Methods
Organs can be cultured on the surface of some sort of inert sponge
material soaked with a fluid medium (see p. 78). Trowell (1952) used
cotton wool soaked in serum-saline, and the cotton wool had to be
prepared in a special way so as to provide an absolutely flat surface.
Moscona and Moscona (1953) used a cellulose disc (prepared from
cultures of Acetobacter xylinum) soaked in serum-saline and placed this
in the watch-glass of Fell's apparatus. These methods produced satisfactory cultures but they did not properly solve the problem. Although
fluid medium was added initially, subsequent recovery or changing of
A . M O S C O N A , O . A . T R O W E L L A N D E . N. W I L L M E R
certain amino acids and vitamins (Wolff, Haffen, Kieny and Wolff,
1953). These and similar methods have been used in the laboratories
of Spratt and of Wolff for the culture of whole embryos and parts
thereof and also for the growth of a variety of embryonic organ
rudiments (see Chapter 15).
Trowell (1952) cultured mature organs on a medium of serum-agar,
the final agar concentration being l-3°/o. The medium was contained
in a small glass cup which was enclosed in a sealed Perspex (Lucite)
chamber filled with oxygen.
A difficulty arises when thin sheets of material such as skin, diaphragm or mesentery are cultured on agar or on a plasma clot. Instead
of staying extended, the tissue tends to roll up into a ball because it
cannot adhere to the slippery surface. The difficulty can be overcome
by first laying a piece of lens paper or rayon fabric on the agar or
plasma clot, but it is easier to use other methods employing lens paper
or rayon, which will be described in the next section. Lens paper is a
very thin open-texture paper supplied for cleaning microscope lenses.
When embryonic organ fragments are cultivated they become encapsulated by a migration of cells from certain parts of the cut surface. This
leads to some reorganization of the organotypic structure which may
be undesirable. Wolff (1960) has found that this encapsulation can
be prevented if the culture is wrapped in vitelline membrane (from
hen's egg) before it is planted on the agar.
From the point of view of the survival of the culture, these agar
methods are quite satisfactory; indeed, the results have not been
bettered by any of the later methods, but there remains the technical
difficulty that the medium cannot be changed, added to or analysed
without transplanting the cultures. There was still the need to devise
a method in which the medium was fluid and readily interchangeable,
and the various ways of doing this will now be described.
E. O R G A N S ON A FLUID MEDIUM
1. "Sponge" Methods
Organs can be cultured on the surface of some sort of inert sponge
material soaked with a fluid medium (see p. 78). Trowell (1952) used
cotton wool soaked in serum-saline, and the cotton wool had to be
prepared in a special way so as to provide an absolutely flat surface.
Moscona and Moscona (1953) used a cellulose disc (prepared from
cultures of Acetobacter xylinum) soaked in serum-saline and placed this
in the watch-glass of Fell's apparatus. These methods produced satisfactory cultures but they did not properly solve the problem. Although
fluid medium was added initially, subsequent recovery or changing of