Chronaximetric Examinations in B Avitaminosis during Pregnancy.

In 1929 Lewy and Weisz (1) stated that persons having contact with lead exhibited an increase in the excitability of the nerves and muscles which could be demonstrated chronaximetrically several months before clinical symptoms appeared. That this method might prove valuable as a means of detecting preclinical evidence of peripheral neuritis due to vitamin B deficiency was suggested in 1934 when Lane and Lewy (2) encountered chronaximetric changes in a group of factory workers taking a vitamin B deficient diet but in whom clinical evidence of vitamin B deficiency had not yet developed. To test further the value of this method in demonstrating early vitamin B deficiency, repeated chronaximetric examinations were made upon the group of pregnant women described by Elsom (3) in the preceding paper. Examinations were carried out early in the observation of these subjects, after addition to the diet of yeast or of liver extract and following delivery. The results of these examinations are given in the present communication.