IV. ACTION OF MORPHOSTATIC SUBSTANCES
165
the tumours. Only injections placed in the tissues immediately adjacent to the tumour proved to be efficient. Sträuli found that transplants
6 days old which grew rapidly in untreated control hosts, responded
strongly to the treatment by combined morphostatic substances. In all
cases in which the combined morphostatics were injected in the neighbourhood of the tumour, the tumour transplants responded by regression.
The synoptic table (Fig. 5) shows 4 different types of tumour reaction.
Whereas the untreated controls continued their growth, a regression
took place during the first days of treatment in all tumours. A shorter
treatment which comprised 15 daily injections could not permanently
suppress tumour growth. But in 25% of the cases after a treatment of
20 days there occurred a complete regression of tumour tissue. Spontaneous regressions in control animals occur only exceptionally. The
local treatment of the tumours did not modify the vitality of the
tumour bearing hosts.
2. The importance of the experimental procedure
for the regression effect in tumours
Like the experiments of other authors our results demonstrate clearly
enough how difficult a successful chemotherapy of tumours in mammals
is. The following variable factors have to be tested:
(1) Whether the tumours to be tested react rapidly or only with
difficulty to chemical treatment (Oettel and Wilhelm, 1957).
(2) The age of the implanted tumour tissue (see the results of Sträuli
mentioned above).
(3) The kind of morphostatic substance and their application (single
substances or synergistic combinations; intravenous total treatment of
the host or local treatment of the adjacent tissues of the host).
(4) The individual growth reaction and a suitable method for
statistical evaluation.
The presence of different variable factors in the chemotherapy of
tumours creates a favourable situation for the tumour biologist. It is
therefore possible to combine optimal conditions for the chemotherapy
of definite tumours. On the other hand there might be created other
conditions which make it difficult to inhibit completely tumour growth.
For favourable conditions we may predict that sensitive and relatively
young tumours may be entirely suppressed by an appropriate treatment
with synergistic morphostatic substances in loco. This situation opens a
new field of systematic investigations for successful chemotherapy of
mammalian tumours. Investigations of this type can be accomplished,
regardless of the biochemical basis of growth. They only require well
designed tumour biological experiments. This is true also for the pro-
165
the tumours. Only injections placed in the tissues immediately adjacent to the tumour proved to be efficient. Sträuli found that transplants
6 days old which grew rapidly in untreated control hosts, responded
strongly to the treatment by combined morphostatic substances. In all
cases in which the combined morphostatics were injected in the neighbourhood of the tumour, the tumour transplants responded by regression.
The synoptic table (Fig. 5) shows 4 different types of tumour reaction.
Whereas the untreated controls continued their growth, a regression
took place during the first days of treatment in all tumours. A shorter
treatment which comprised 15 daily injections could not permanently
suppress tumour growth. But in 25% of the cases after a treatment of
20 days there occurred a complete regression of tumour tissue. Spontaneous regressions in control animals occur only exceptionally. The
local treatment of the tumours did not modify the vitality of the
tumour bearing hosts.
2. The importance of the experimental procedure
for the regression effect in tumours
Like the experiments of other authors our results demonstrate clearly
enough how difficult a successful chemotherapy of tumours in mammals
is. The following variable factors have to be tested:
(1) Whether the tumours to be tested react rapidly or only with
difficulty to chemical treatment (Oettel and Wilhelm, 1957).
(2) The age of the implanted tumour tissue (see the results of Sträuli
mentioned above).
(3) The kind of morphostatic substance and their application (single
substances or synergistic combinations; intravenous total treatment of
the host or local treatment of the adjacent tissues of the host).
(4) The individual growth reaction and a suitable method for
statistical evaluation.
The presence of different variable factors in the chemotherapy of
tumours creates a favourable situation for the tumour biologist. It is
therefore possible to combine optimal conditions for the chemotherapy
of definite tumours. On the other hand there might be created other
conditions which make it difficult to inhibit completely tumour growth.
For favourable conditions we may predict that sensitive and relatively
young tumours may be entirely suppressed by an appropriate treatment
with synergistic morphostatic substances in loco. This situation opens a
new field of systematic investigations for successful chemotherapy of
mammalian tumours. Investigations of this type can be accomplished,
regardless of the biochemical basis of growth. They only require well
designed tumour biological experiments. This is true also for the pro-