189bj MICROSCOPICAL JOURNAL 385 



Special Staining Methods in Microscopy, Relative to Animal 

 Tissues and Cells. 



5. The Mucin Constituents oe Neurofibromata and of the Cen- 

 Trai, Nervous System. By Dr. P. G. Unna. Translated by A. 

 Habermaas, M. D., St. Louis. 



The beautiful specific red stain, which all mucin con- 

 stituents of the skin (mast-cells, the mucin metamor- 

 phosis of collagen and epithelium) assume when treated 

 with the polychrome-methylene-blue and properly decol- 

 orized, has led to some new discoveries which I shall 

 briefly describe. 



Some time ago I was impressed with the number of 

 mast-cells in the neurofibrous tissue of a neurofibroma of 

 the skin. In distinction to the i-utaneous tissue surround- 

 ing it, which manifests the ordinary collagen, the tissue 

 of the nodule, as the epoch-making work of Ruckling- 

 housen has shown, consists of a very peculiar variety of 

 collagen. The latter is not only destitute of elastin, for 

 this peculiarity it shares with other varieties of fibromata 

 but is also peculiarly transparent and soft and manifests 

 a remarkably regular structure, which corresponds to that 

 of the epineurium. Unlike the surrounding cutis, when 

 treated by the orcein-methylene-blue method, it presents 

 an aflBnity for the methylene-blue instead of the orcein 

 and assumes so marked a stain that in a well-prepared 

 intercellular stain it can be distinguished from the adja- 

 cent tissue by the naked eye. It consists of a soft, 

 rather amorphous, collagenous material, showing no fib- 

 rillar bundles, and in which at regular intervals spindle- 

 cells, meagre in protoplasm, with rod-like nucleus, as well 

 as large mast-cells, of a remarkably round form, are im- 

 bedded. If the neurofibrous tissue within the cutis were 

 not difl'erentiated from that of ordinary cutaneous fib- 

 romata by the fact that it arises from a nerve, that it 

 develops from the connective tissue of the epineurium, 

 and by the peculiar variety of its collagen, the great 



