The certified diagnosis of tuberculosis in man or in animals rests on the finding of the tubercle bacillus in the smear microscopically, in the culture tube macroscopically verified by microscopic examination, and by producing the disease in a highly susceptible species of animal such as the guinea-pig,1and verifying the results microscopically as well as by the gross appearances of the generalized disease in these animals. The examination of the stained smear has long enjoyed the almost solitary preference of clinicians on account of its simplicity of performance yet with no regard for its delicacy or value. In the face of the presence of an evident ulcerative tuberculous condition, now and again repeated microscopic examinations of stained specimens are returned as negative in the experience of practically all physicians dealing with numbers of tuberculous cases. Attempts to improve decidedly the staining technic have been without much avail and today