384 THE BRAIN OF MAMMALS, BY TH. MEYNERT. 



of capillaries), is certainly dependent upon the accumulation of 

 nerve corpuscles containing pigment, so that those layers 

 through which, like the third of fig. 234, they are sparsely 

 scattered, are recognised as more or less pale and amorphous 

 concentric intermediate striae. 



The non-nervous grey substance consists of an amorphous 

 and a formed portion. The diffused or amorphous material or 

 matrix, which becomes faintly stained with carmine, exhibits a 

 cloudiness that perhaps is only consequent upon death, and is 

 due to the presence of dark molecules that are still seen as such 

 with the highest powers, together with branches of the finest 

 fibres, and are not altogether referable to the transverse sec- 

 tions of those fibres. Deiters holds as an immediate consequence 

 of the cell theory, that the matrix proceeds from a differentia- 

 tion of the coalesced protoplasm of the formative cells probably 

 occurring at the time when these have not undergone differen- 

 tiation into the nervous and non-nervous tissues. He regards 

 the free nuclei of the cerebral cortex as alone representing the 

 formed equivalents of cells. I must, however, assert the con- 

 stant presence in this organ also of cells which he admits to 

 exist in the allied stroma of the gelatinous substance of the spinal 

 cord and of the medulla oblongata ; viz., stellate cells, provided 

 with a little protoplasm and a multitude of very fine branched 

 processes. This moreover agrees with the views of Kolliker 

 respecting the same substance. These bodies, which are in 

 healthy states extraordinarily pellucid (and thus produce the 

 appearance of free nuclei), assume in pathological conditions the 

 most grotesque forms, especially in circumstances occasioning 

 the arrest of the discharge of interstitial serum into the peri- 

 vascular lymph spaces contracted in consequence of hypersemia, 

 but still more in degeneration of the lymphatic glands of the 

 head and neck. Similar corpuscles form the bridge-like threads 

 described by Roth, which, extending from the margin of the 

 perivascular spaces, cross the lacunae. Hence the matrix of 

 the grey matter is traversed by a plexus of processes from 

 non-nervous cells. The nuclei of these cells have a diameter 

 of 9 10 fi. On the surface of the first layer of the cortex is a 

 very delicate medullary lamina or investment of extremely 

 fine varicose nerve fibres which decussate with one another in 



