1896] MICROSCOPICAL JOURNAL. 133 



permanganate of potassium when the whole changes at 

 once into a violet, but the protoplasm and muscle bundles 

 are so strongly colored that it becomes necessary to de- 

 colorize with acid-salt alcohol without decolorizing the 

 last named tissue. This change may be utilized in order 

 to decolorize the collagen tissues which are not so much 

 affected by methyl-blue, and this shows a picture of the 

 smooth muscles and protoplasm in deep violet on a color- 

 less backgroud. This methyl-blue-potassium permauga- 

 nate alcoholic treatment of the skin muscles is carried 

 out in the following manner : 



The section is put for ten minutes in the polychrome 

 methyl-blue solution, then washed in water, then put for 

 10 minutes in a 1 per cent solution of permanganate of 

 potassium, fixed, and lastly washed in water again and 

 decolorized in acid alcohol (1 per cent HCl) until tiie 

 collagen background shows itself white. Here follows a 

 washing in absolute alcohol^ then cleared in oil and 

 mounted in balsam. 



A cell and cell-like substances show in such prepara- 

 tions an equal violet color. The epidermis as well as the 

 prickle cells are too deeply stained to permit this struc- 

 ture to be well recognized ; but all delicate parts of this 

 nature, the coil glands, the blood-vessels, capillaries, all 

 connective tissue cells and lastly the muscles, are sharply 

 defined against the unstained collagen, and at the same 

 time permit their structure, especially the cell walls, 

 such as the contours of the muscle spindles, to appear 

 clearly. In addition to the deep staining of the cell nuclei 

 and muscles, the method furnishes in this respect very 

 useful general pictures. 



As important as the differentiation of collagen is that 

 of elastin, on account of the exact functional relations 

 between elastin and muscle substance : in all cases in 

 which elastin is not specifically stained will it be seen in 

 the color of the collagen and not in that of muscle sub- 



