X-ray studies on tobacco mosaic virus

1. 1. Confirming earlier work, the 37% survival dose, D 0, for inactivation by x-rays of TMV was found to be 2.3 × 10 5 r., which corresponds to a target volume of 4.1 × 10 −18 cc., or about 1 12 the anhydrous particle volume. 2. 2. The stability at 80 °C. of survivors of 5 D 0 was found to be the same as that of unirradiated virus, in support of the view that x-ray inactivation is an all-or-none reaction. 3. 3. Reasons are given in support of the view that the target may be the nucleic acid.