IN the course of analyses of vegetable foods with the view of evolving an entirely vegetable dietary which would be optimal in respect of protein, determinations of essential amino-acids were carried out on two legumes, Mysore dhal or lentil (Lens esculenta], and green gram or mung (Phaseolus vulgaris, Roxburgh). The determinations were carried out by microbiological assay. Leuconostoc mesenteroides and Streptococcus faecalis were used with various media1 in the assay of lysine, methionine, isoleucine and phenylalanine, and Streptococcus faecalis in the assay of valine, leucine and threonine.