1. Certain water-soluble esters of long chain fatty acids (in particular of oleic acid) favor submerged and diffuse growth of mycobacteria throughout the depth of synthetic liquid media.
2. Esters of oleic acid increase considerably the amount of growth yielded by avian strains in synthetic media.
3. The addition of serum albumin to synthetic liquid media permits visible growth of minimal inocula of virulent human tubercle bacilli (10–8 mg.) within 11 to 15 days.
4. Cultures growing diffusely in media containing the water-soluble esters— with or without albumin—consist of cells of classical morphology and staining properties, which again exhibit the usual mode of growth when returned to the standard synthetic or egg yolk media.