Certain coloring matters are known which, when administered to the living animal, stain portions of its tissues without destroying the life of the animal or that of the affected tissue. The first scientific use of observations of this order is attributed by Fischel1 to Misaud (1567), who found that when animals were fed with madder the actively growing portions of the bones were stained red. The long continued researches of Ehrlich on the physiological relationships of the anilin dyes has resulted in many additions to the list of substances exhibiting this form of activity, and it is to be foreseen that much valuable information will in the future be derived from the systematic use of such methods.
Recently Goldman,2 in the course of other studies, has applied vital staining methods to a study of tuberculosis as produced by the inoculation of mice. He used isamin-blue for this work.