Measurement of vital capacity in asthmatic subjects receiving histamine and acetyl-beta-methyl choline. A clinical study

1.1. Changes in the vital capacity were studied following the injection of acetyl-beta-methyl choline and histamine in forty asthmatic subjects. 2.2. Analysis of the results with respect to the pulmonary responsiveness to the two drugs on the one hand and various clinical features on the other indicate that: (a) patients with severe asthma were most responsive to the two drugs and those with mild asthma were least responsive; (b) patients with asthma of very recent origin or those whose asthma had ceased or markedly diminished were either slightly responsive or not responsive at all; (c) age, sex, the presence of hay fever, eczema, or urticaria in the subject or the subject's family appeared to have no influence on the susceptibility to the two drugs. It is concluded that of all the factors considered, asthma was the only one which appeared to have a direct influence on the pulmonary responsiveness to histamine and acetyl-beta-methyl choline.