258
MAURICE WELSCH
mechanisms directly operating against microorganisms in natural and
acquired immunity. Although this inclusion brings us back closer to the
original broad notion of antibiosis, it would probably be, at the present
time, a troublesome cause of confusion, inasmuch as its unavoidable
consequence would be a splitting of immunology into two parts according to whether the substances studied do or do not have, directly or
indirectly, some antimicrobial property.
A further step was taken when the name antibiotic was applied not
only to naturally occurring antimicrobial substances but also to synthetic
chemicals exerting a noxious effect upon microorganisms, even though
they were not copies of natural models (17a). Physicians have quite
often adopted this meaning of the word while restricting it, on the other
hand, to chemicals that have a low enough toxicity for animal cells and
organs so that they can be used for the therapy of microbial diseases.
Certainly, the inclusion in the class of antibiotics of substances artificially
produced by man's unique intellectual abilities and used by him to
destroy inimical organisms is well in keeping with the original broad
concept of antibiosis.
The final step to be taken, after which nothing would be left of
Waksman's definition except the all-important provision that antibiotics
are chemical substances, was to replace the property of antimicrobial
activity by the more general one of toxicity for any kind of cell or
organism. After such a broadening of the definition, the whole of toxicology would fall within the province of antibiotics, among which would
be included a large number of substances playing certainly no part in
any natural manifestation of antibiosis. In practice, the use of the word
was extended only to include substances able to destroy not only microorganisms, but animal parasites, viruses, or neoplastic cells as well.
Although there is evidently no a priori reason for antimicrobial properties
to be associated in a given chemical with antiviral or anticancer properties, the success of antibiotics in the chemotherapy of bacterial and
fungal diseases was an incentive for the search of biologically produced
agents potentially usable for the treatment of virus diseases (17b) and
cancer (17c). If relatively few substances of practical importance have
so far been thus obtained, the number of antiviral and anticancer agents
already recognized is far from negligible.
Exactly as in the case of the word antibiosis, the word antibiotic has
been used by various authors with widely different meanings. However,
it has always been applied only to chemical substances of various origin,
possessing a more or less extensive range of toxicity. Therefore, whether
one considers either their production by, or their action upon, living
MAURICE WELSCH
mechanisms directly operating against microorganisms in natural and
acquired immunity. Although this inclusion brings us back closer to the
original broad notion of antibiosis, it would probably be, at the present
time, a troublesome cause of confusion, inasmuch as its unavoidable
consequence would be a splitting of immunology into two parts according to whether the substances studied do or do not have, directly or
indirectly, some antimicrobial property.
A further step was taken when the name antibiotic was applied not
only to naturally occurring antimicrobial substances but also to synthetic
chemicals exerting a noxious effect upon microorganisms, even though
they were not copies of natural models (17a). Physicians have quite
often adopted this meaning of the word while restricting it, on the other
hand, to chemicals that have a low enough toxicity for animal cells and
organs so that they can be used for the therapy of microbial diseases.
Certainly, the inclusion in the class of antibiotics of substances artificially
produced by man's unique intellectual abilities and used by him to
destroy inimical organisms is well in keeping with the original broad
concept of antibiosis.
The final step to be taken, after which nothing would be left of
Waksman's definition except the all-important provision that antibiotics
are chemical substances, was to replace the property of antimicrobial
activity by the more general one of toxicity for any kind of cell or
organism. After such a broadening of the definition, the whole of toxicology would fall within the province of antibiotics, among which would
be included a large number of substances playing certainly no part in
any natural manifestation of antibiosis. In practice, the use of the word
was extended only to include substances able to destroy not only microorganisms, but animal parasites, viruses, or neoplastic cells as well.
Although there is evidently no a priori reason for antimicrobial properties
to be associated in a given chemical with antiviral or anticancer properties, the success of antibiotics in the chemotherapy of bacterial and
fungal diseases was an incentive for the search of biologically produced
agents potentially usable for the treatment of virus diseases (17b) and
cancer (17c). If relatively few substances of practical importance have
so far been thus obtained, the number of antiviral and anticancer agents
already recognized is far from negligible.
Exactly as in the case of the word antibiosis, the word antibiotic has
been used by various authors with widely different meanings. However,
it has always been applied only to chemical substances of various origin,
possessing a more or less extensive range of toxicity. Therefore, whether
one considers either their production by, or their action upon, living