STUDIES IN THE VARIABILITY OF TUBERCLE BACILLI.: III. INFLUENCE OF X-RAYS UPON DISSOCIATION

Abstract

It is shown that X-ray treatment of cultures of a rapid-growing strain of bovine tubercle bacillus showing a tendency to change from R to S promoted the change to a considerable degree. Stable R cultures of the same species are unaffected. Larger doses produce a lethal effect.Protective colloids such as gelatine or blood serum added to the suspension reduce the effect of the irradiation.Non-acid-fast bacteria are shown to be much less sensitive to the effects of X-rays, as no change in the rate of dissociation has been observed in actively dissociating cultures with twice the dosage to which tubercle bacilli were exposed.