32 THE STIUCTLKK OF CHUOMOPHILK CP^LLS OF THF NKinOlS 8YSTKM. 



Homo chroiiiophile cells differ only from other cells by a slight increase in the 

 amount and in the intensity of the staining of the mitochondria (figure 1 ). There is 

 apparently no corresponding change in the Nissl substance and the morphology of 

 the mitochondria is unaltered. 



Other cells show a remarkable increase in the number of mitochondria. For 

 example, a cell (figure 2) fre(|uently contains three or four times as many mito- 

 chondria as its neighbor; this increase in mitochondria is associated with a slight 

 but perceptible increase in the amount of the diffuse Nissl substance in the cyto- 

 plasm and witli a darker staining of the acidophilic and basophilic nucleoli and the 

 grovmd-substance of the nucleus, (^ells in this condition show no evidence of shrink- 

 age. They may be recognized in C'ajal preparations (figure 7) by the changes in 

 the nucleus and the \issl substance. The Cajal i)reparations show that the cana- 

 licular apparatus is unaltered. 



There may be a great increase in the Nissl substance, which is present as a 

 diffuse deposit (figure 3). At the same time some of the mitochondria oft(>n lose 

 their discrete outlines and seem to merge into the surrounding cytoplasm. Mito- 

 chondria may not be very numerous in cells of this kind. The nucleus stains 

 intensely and a few clear canals maj' be seen in its vicinity. The cell has ai)pai-entl_\- 

 shrinkage spaces on either side of it. Prej^arations, made by fixing in alcohol and 

 staining with toluidin l)lue, contain cells in which the Nissl .substance is in this con- 

 dition and Cajal preparations show that the canals are unaltered. 



Figure 4 illustrates a cell in a rather more advanced stage of chromophilia. 

 In this cell there is an unusually large amount of Nissl substance and there are 

 further evidences of tlie disappearance of formed mitochondria, especially in the 

 cell process. The outlines of the nucleus can barely be made out. The canalicular 

 apparatus shows no modifications either by this method or by the Cajal technicjue. 



A very interesting condition is shown in figure o. Here, with this degree of 

 differentiation, only a few typical mitochondria persist near the origin of the cell 

 process. The Nissl substance is overshadowed by a cloud of material staining 

 the same way as the formed mitochondria do in adjacent cells. Figure 8 illustrates 

 a similar cell in a ( 'ajal preparation. The Nissl substance in it is increased and there 

 is no modification in the blackened canalicular apparatus. Cells in this condition 

 are often shrunken. It is difficult to determine whether the shrinkage is the expres- 

 sion of an actual diminution in the .size of the cells during life, or whether it is simply 

 the result of a difference in the reaction of chromojihih' cells to the fixation and sub- 

 sequent treatment. The presence of what appear to be shrinkage spaces around the 

 cells .seems to indicate that it is in reality due to the technifiue employed, because if, 

 on the other hand, it was due to a decrease in the size of the cell during life, one 

 would expect the space to be filled uj) by a shifting of neighboring structures. It 

 may be emphasized that the fact that other cells, in actual contact with chromoi)hile 

 cells, show no signs whatever of .shrinkage must be regarded as one of the distinctive 

 properties of cells in the chronioi)hilic condition. Then^ is, of course, still another 

 interpretation, namely, that the spaces in (juestion are uiuisually large i)erineuronal 

 spaces, the enlargement l^eing in some way connected with the difference in the 

 physiological condition of chromophile cells as contrasted with other cells. 



