Word: paramecia
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...Killers. Classical genetics took some punishment from Professor T. M. Sonneborn of Indiana University, who headed a symposium on paramecia...
...paramecium is a minute one-celled animal which multiplies both non-sexually (by simple division) and by a kind of primitive pairing. Several years ago, Dr. Sonneborn discovered that special strains of paramecia give off a poison (paramecin) that kills normal paramecia. The "killers" differ from the "sensitives" in only one known respect: the amount of a substance called "kappa" which they contain...
...paramecium, to rate as a killer, has to contain at least 200 particles of kappa. If it has less, it is a sensitive, and can be destroyed by killers with plenty of kappa. Dr. Sonneborn discovered that sensitive paramecia can be turned into killers at will. He put sensitive paramecia into a solution of mashed killer paramecia. Half of the sensitives absorbed kappa particles, which turned them into killers. Their descendants were killers...
...proper scientist should, Dr. Sonneborn spoke modestly of his achievement. But it is none the less notable: he had given his sensitive paramecia an acquired characteristic (the killing ability) which they transmitted by heredity to their offspring. Classical genetics has been saying firmly that it just cannot be done...
Roskin proceeded to test the serum of cancerous rabbits, then of human patients, found to his delight that when properly prepared, it was highly toxic to paramecia. No other serum, not even that from patients with benign tumors, produced the same effect. The paramecia-killing power of serum from animals with implanted cancer varied with the type of cancer. A cancer can sometimes be detected two days after it is implanted, before any visible tumor has developed...