Yoshida et al. 1957) showed that preparations of cell-wall material made from BacilluB 8ubtilis are likely to be more complicated than those from some other Gram-positive organisms such as Micrococcus ly8odeikticu8, Staphylococcus aureus or BacilluB megateriurn. Preparations from these last-named organisms revealed, after acid hydrolysis, the presence of only three or four amino acids as major components together with two amino sugars and in some instances one or two hexoses (Salton, 1953; Cummins & Harris, 1956; Salton & Milhaud, 1959). In some strains of the two coccal species up to 80-90 % of the wall is made from four amino acids * On leave from the State Institute of Hygiene, Warsaw.