44
A . M O S C O N A , O . A . T R O W E L L A N D E . N . W l L L M E R
as is shown in Fig. lc. When the plasma is firmly clotted, a supernatant fluid is added and the whole tube mounted on a wheel so arranged in the incubator that the tube rotates slowly (about 1 rev/min)
in a horizontal position, thus ensuring better mixing and aeration of
the nutrient fluid. Again, the tubes may be filled with gas mixtures
of known composition and the side of the tube where the tissues are
explanted can be constructed as an optically flat surface in order to
facilitate direct observation of the cultures, which is otherwise rather
difficult in roller tubes. Some tissues have been grown successfully by
this method even without the use of a plasma clot, provided that
sufficient time is allowed for the tissues to adhere to the glass before
rotation starts. Alternatively the tubes can be lined with reconstituted
collagen, as this facilitates adhesion and spreading of the cells on the
surface (Ehrmann and Gey, 1956).
In order to eliminate the necessity for disturbing the tissue, particularly when it is likely that a permanent microscopic preparation may
be required, it is possible, both in flasks and in roller tubes (if they have
wide necks), to grow the tissue on a coverslip which either sits on the
bottom of the flask attached by an intervening drop of plasma as in
Maximow's original (1925) two-coverslip method for hanging-drop
cultures, or fits loosely into the roller tube and gently slides round as
the tube rotates. This latter method has been found to be very satisfactory for cultures of neural tissues. It goes, though perhaps inaccurately, by the attractive name of the "flying coverslip" and in some
instances it has certainly produced a magic carpet of cells for the
results of the long-continued cultures of neural tissues by Costero
and Pomerat (1951) can surely be described in this manner. With
hexagonal tubes particularly, the coverslips can be attached to the
glass with drops of plasma and removed as required for washing the
tissues in different media, for fixation or for other purposes.
An important variant of the roller-tube culture was developed by
Leighton (1951) who used small rectangular cushions of very wellwashed, cleaned and sterilized commercial cellulose sponge upon which
to support several fragments of tissue. The sponge was placed on the
side of the tube and the tissues attached to it by plasma. In this way
the whole sponge fragment can be gently bathed with fluid medium
and the cells invade the cellulose sponge where they may develop
orderly tissues. In fact, the growth tends to be organotypic and is
particularly suitable for studying tissue interactions.
E. T U B E C U L T U R E S
Cultures can also be grown in small stationary test tubes or similar
A . M O S C O N A , O . A . T R O W E L L A N D E . N . W l L L M E R
as is shown in Fig. lc. When the plasma is firmly clotted, a supernatant fluid is added and the whole tube mounted on a wheel so arranged in the incubator that the tube rotates slowly (about 1 rev/min)
in a horizontal position, thus ensuring better mixing and aeration of
the nutrient fluid. Again, the tubes may be filled with gas mixtures
of known composition and the side of the tube where the tissues are
explanted can be constructed as an optically flat surface in order to
facilitate direct observation of the cultures, which is otherwise rather
difficult in roller tubes. Some tissues have been grown successfully by
this method even without the use of a plasma clot, provided that
sufficient time is allowed for the tissues to adhere to the glass before
rotation starts. Alternatively the tubes can be lined with reconstituted
collagen, as this facilitates adhesion and spreading of the cells on the
surface (Ehrmann and Gey, 1956).
In order to eliminate the necessity for disturbing the tissue, particularly when it is likely that a permanent microscopic preparation may
be required, it is possible, both in flasks and in roller tubes (if they have
wide necks), to grow the tissue on a coverslip which either sits on the
bottom of the flask attached by an intervening drop of plasma as in
Maximow's original (1925) two-coverslip method for hanging-drop
cultures, or fits loosely into the roller tube and gently slides round as
the tube rotates. This latter method has been found to be very satisfactory for cultures of neural tissues. It goes, though perhaps inaccurately, by the attractive name of the "flying coverslip" and in some
instances it has certainly produced a magic carpet of cells for the
results of the long-continued cultures of neural tissues by Costero
and Pomerat (1951) can surely be described in this manner. With
hexagonal tubes particularly, the coverslips can be attached to the
glass with drops of plasma and removed as required for washing the
tissues in different media, for fixation or for other purposes.
An important variant of the roller-tube culture was developed by
Leighton (1951) who used small rectangular cushions of very wellwashed, cleaned and sterilized commercial cellulose sponge upon which
to support several fragments of tissue. The sponge was placed on the
side of the tube and the tissues attached to it by plasma. In this way
the whole sponge fragment can be gently bathed with fluid medium
and the cells invade the cellulose sponge where they may develop
orderly tissues. In fact, the growth tends to be organotypic and is
particularly suitable for studying tissue interactions.
E. T U B E C U L T U R E S
Cultures can also be grown in small stationary test tubes or similar