Abstract
In 19 cases of lymphocytic meningitis, the radioactive bromide partition test showed that four were tuberculous and 15 viral in origin. In all the tuberculous cases the serum/cerebrospinal fluid bromide ratio was below a critical value of 1.6, and in all the cases of viral meningitis the ratio was above this value. The test may be particularly helpful when diagnosis is difficult. The test may prove to be a valuable and justified additional procedure in the early diagnosis of tuberculous meningitis.