The finding of foci of muscle atrophy in vitamin B6deficient rats1and the production of tremors and convulsions in rats after the administration of massive doses of synthetic vitamin B62indicated that vitamin B6might have some effect on muscle action. Accordingly it was decided to determine whether 2-methyl3-hydroxy-4,5-dihydroxy methyl pyridine (vitamin B6) had any effect on the muscular dystrophies of man. This communication deals with six cases of pseudohypertrophic muscular dystrophy which were treated with the synthetic vitamin. REPORT OF CASES Case 1.— A boy was first seen in February 1938 at the age of 4. For one year prior to this time his mother noted that he was reluctant to walk, walked unsteadily requiring a wide base, fatigued easily on walking and had difficulty in rising from a supine position. In January 1939 he had to pull himself upstairs by sheer