386 THE AMERICAN MONTHLY [Nov. 



number, regular distribution and general round form of 

 its mast-cells would distinguish it beyond doubt. 



The discovery referred to pertains to these peculiarly 

 distributed and formed mast-cells of neurofibromata. 

 In some recently prepared nodules of such a neurofibroma 

 the mast-cells under the new stain (polychrome-methylene 

 blue, glycerin-ether mixture) Jippear twice the usual size. 

 This is due to the staining of a large round area, in 

 whose center the mast-cell itself lies, consisting of a blue 

 nucleus and an area of dark-red granules. Under higher 

 power this area is foung to consist of a fine spongy 

 reticulum, and is not granular, although it takes up the 

 same red stain as the granules. We have here to deal 

 with a spongioplasm peculiar to the mast-cells. A more 

 minute examination of these cells shows that the area 

 described does not surround the nucleus with its granular 

 area equally on all sides, but only on one side. Most 

 often the red spongioplasm, resembling an open shell, 

 and in which the nucleus and its granules lie, is found 

 more or less deeply situated. Sometimes processes of 

 the spongioplasm surround the contained nucleus, meet- 

 ing from both sides, so that the latter appears to be 

 enveloped in a cloak, though not completely. In other 

 instances the area is represented by an irregular plate, 

 giving off thread-like processes in various directions and 

 upon which the mast-cell (nucleus and granules) appears 

 to lie These cells somewhat resemble the "winged-cell" 

 of tendons. 



Again, in this instance bell-shaped, spongy masses are 

 observed, with broad, veil-like processes, in whose con- 

 cavity the nucleus and its granules lie. 



That the area surrounding the mast-cell really belongs 

 to the latter, and is not an independent structure surround- 

 ing the cell, is proven by the many pictures in which 

 the spot can be clearly distinguished where the cell com- 

 municates with the mast-shell. At this point, the proto- 



