1. I N T R O D U C T I O N
9
The necessity for a synthetic or defined medium, whose composition
was completely known, was early seen by Philip White (1946), who,
interestingly enough, entered the field of Tissue Culture from the
botanical side; thus the basic efforts of Albert Fischer (1948) in this
direction were quickly followed up by further developments by White
(1949) and by Raymond Parker and his school (Morton, Morgan and
Parker, 1950), Charity Waymouth (1955), Earle and his school (Evans,
Bryant, Fioramonti, McQuilkin, Sanford and Earle, 1956; McQuilkin,
Evans and Earle, 1957) and more recently by Eagle, Oyama and Levy
(1957) and others (Chapter 3). All these various chemically defined
media may well turn out to be rather more complex than they need to
be, in the sense that they have mostly been devised on the principle
that every possible requirement of cells should be present at first, in
order to ensure the full activity of the cells, and then simplification may
become possible by the elimination of the separate constituents one at
a time, with a study of the effects produced. It is easier to proceed in
this way from a medium which is adequate than to build up a satisfactory medium by the addition of one substance after another. The
reason for this is that substances are often active in combination with
others, but inactive if present alone. Elaborate as some of these defined
media are, there are only one or two types of cell that have so far been
satisfactorily cultured in them without the addition of any serum,
serum derivative, tissue extract or other biological fluid; so the dream
of an entirely synthetic medium for Tissue Culture in general is still to
be realized in full. A detailed discussion of these media will be found in
Chapter 3 but it should be emphasized that the construction of defined
media has now reached such a level that cultures of many types of cells
can at the present time be made on a much more wholesale scale than
ever seemed likely in the days when plasma and embryo juice were the
usual constituents of the Tissue-Culture medium. However, another
major advance in technique has also contributed to this success and the
story of this advance is not without interest.
The story, like many another physiological story, goes back to
Claude Bernard (1856) who began to seek an explanation for the earlier
observations of Hunter that while the living stomach and intestine are
not digested by their own juices, they are rapidly digested after death.
Fermi (1910) extended these observations and showed that many living
cells and organisms can withstand prolonged treatment with high concentrations of trypsin. Peyton Rous and Jones in 1916 were the first to
make preparations of isolated cells from tissues by using trypsin to free
them from their matrix. Twenty-one years later Simms and Stillman
(1937) used trypsin to activate tissues from adult animals before explanting them in plasma cultures and found that cells emerged more
B*
9
The necessity for a synthetic or defined medium, whose composition
was completely known, was early seen by Philip White (1946), who,
interestingly enough, entered the field of Tissue Culture from the
botanical side; thus the basic efforts of Albert Fischer (1948) in this
direction were quickly followed up by further developments by White
(1949) and by Raymond Parker and his school (Morton, Morgan and
Parker, 1950), Charity Waymouth (1955), Earle and his school (Evans,
Bryant, Fioramonti, McQuilkin, Sanford and Earle, 1956; McQuilkin,
Evans and Earle, 1957) and more recently by Eagle, Oyama and Levy
(1957) and others (Chapter 3). All these various chemically defined
media may well turn out to be rather more complex than they need to
be, in the sense that they have mostly been devised on the principle
that every possible requirement of cells should be present at first, in
order to ensure the full activity of the cells, and then simplification may
become possible by the elimination of the separate constituents one at
a time, with a study of the effects produced. It is easier to proceed in
this way from a medium which is adequate than to build up a satisfactory medium by the addition of one substance after another. The
reason for this is that substances are often active in combination with
others, but inactive if present alone. Elaborate as some of these defined
media are, there are only one or two types of cell that have so far been
satisfactorily cultured in them without the addition of any serum,
serum derivative, tissue extract or other biological fluid; so the dream
of an entirely synthetic medium for Tissue Culture in general is still to
be realized in full. A detailed discussion of these media will be found in
Chapter 3 but it should be emphasized that the construction of defined
media has now reached such a level that cultures of many types of cells
can at the present time be made on a much more wholesale scale than
ever seemed likely in the days when plasma and embryo juice were the
usual constituents of the Tissue-Culture medium. However, another
major advance in technique has also contributed to this success and the
story of this advance is not without interest.
The story, like many another physiological story, goes back to
Claude Bernard (1856) who began to seek an explanation for the earlier
observations of Hunter that while the living stomach and intestine are
not digested by their own juices, they are rapidly digested after death.
Fermi (1910) extended these observations and showed that many living
cells and organisms can withstand prolonged treatment with high concentrations of trypsin. Peyton Rous and Jones in 1916 were the first to
make preparations of isolated cells from tissues by using trypsin to free
them from their matrix. Twenty-one years later Simms and Stillman
(1937) used trypsin to activate tissues from adult animals before explanting them in plasma cultures and found that cells emerged more
B*