A Method of Differentiating in Sections of Tissue Bacteria Decolorized by Gram's Stain

A number of methods are given in the text books on histological technique for staining in the tissues bacteria which are decolorized by Gram's method, but owing to the fact that the demonstration of the bacteria is accomplished at the expense of the tissue differentiation they have all proved unsatisfactory. Good results are only oecasionally obtained by the ordinary routine eosin-methylene-blue method (recommended in Mallory and Wright's text book on Pathological Technique) and are too ineonstant to be of practical value in staining bacteria in sections. The failure of the method to give constant results does not seem to be the fault of any one step in the teehnique, therefore attempts to correct or modify this method have been unsuccessful. In the course of a study of the histological lesions produced by certain bacteria whieh do not retain the Gram stain, the attempt was made to demonstrate the organisms and at the same time to obtain a clear differentiation of the tissues. The well differentiated eell-picture obtained with the various modifications of Leischman's blood stain (especially that devised by Wright), suggested to me this method, or some modification of it, as a possible means of overcoming the difficulty heretofore encountei'ed. The experiment sueceeded beyond all expectation. The staining solution used is a modification of the Leisch-man-Wright solution; the essential difference being in the amount of eosin used. The ordinary Leisehman stain and the various modifications will not give color differentiation to the tissues. They all stain the tissues uniformly blue with little if any nuclear differentiation so that the bacteria if stained are not distinguish-able.