The tuberculostatic properties of the unsaponifiable fraction of cod liver oil

1. The unsaponifiable fraction of cod-liver oil contains substances which in a concentration of 2 μg per ml of Sauton's medium have a marked inhibitory action on the growth ofM. tuberculosis D328 and the virulent strain A30. 2. Saturated and unsaturateda-glycerylethers are very probably responsible for this activity. 3. Addition of blood serum albumin to the medium gives an important reduction of the growth inhibition by these substances. 4. With analogous fractions of margarine, butter, yolk and beef dripping growth inhibition could not be obtained. 5. The presence of dead Mycobacteria reduces the observed growth inhibition considerably. A quantitative relationship exists between the amount of dead bacteria added and the amount of inhibitor which is neutralised. It could be shown that the inhibitor is adsorbed by the added bacteria. Each bacterium binds 4×107 molecules. Supposing adsorption as a monomolecular layer, this means 1 molecule to about 20 A2 of the bacterial surface. 6. The glycerylether fraction of cod-liver oil (fraction 5) which inhibits in a concentration of 1 μg/ml of Sauton's medium the growth of virulent tubercle bacteria has no favourable action on tuberculosis in guinea-pigs in a daily dose of 25 mg given per os or by subcutaneous injection. Indeed the substance is toxic and oral administration to healthy guinea-pigs causes hyperaemia of the intestinal mesenterium, swollen mesenterial lymphglands and growth of connective tissue (sometimes followed by strangulation of the intestine).