138 PRACTICAL HISTOLOGY. 



columnar epithelium ; the cilia, however, have been destroyed 

 in the hardening process. 



The gray matter with its multipolar cells relatively larger 

 in the anterior horn. The nerve fibres in the white columns 

 mostly cut transversely with the axial cylinders stained. 

 The pia mater sending in here and there well-marked pro- 

 cesses continuous with a fine connective tissue (neuroglia) 

 lying between the nerve elements. The processes contain 

 an elastic tissue which may be shown by pencilling a sec- 

 tion of the hardened cord. In the spinal cord, medulla, 

 and perhaps in other parts at the base of- the brain, the 

 neuroglia is a nucleated connective tissue, the matrix of 

 which is fibrillated. In the cerebrum and cerebellum the 

 matrix appears to be a sort of jelly, but it is difficult to de- 

 fine it exactly. 



b. Mount an unstained T. S. cord in dammar for com- 

 parison with the preceding. 



246. Examine the following preparations : 



a. (L.) V. S. white and gray columns of spinal cord 

 carminised. 



b. (L.) T. S. spinal cord injected. The gray is far 

 more vascular than the white matter. 



2 46 A. Structure of Medulla Oblongata. Examine 

 the following preparations : 



a. (L.) T. S. carminised medulla oblongata through 

 the decussation of the anterior pyramids. Observe the 

 decussation; the enlarged tips of the posterior horns of 

 gray matter, now termed the tubercles of Rolando; the 

 posterior pyramids. 



b. (L.) T. S. carminised medulla through the olivary 

 bodies, and the lower part of the fourth ventricle. The 

 following parts may be recognised from the anterior median 

 line outwards in either half of the medulla. The anterior 

 pyramid without any gray matter. Fibres of the hypoglossal 

 nerve passing to the gray matter at the floor of the fourth 

 ventricle. The olivary fasciculus with its ganglion the 

 corpus dentatum a crumpled sheet of gray matter. Fibres 

 of the vagus nerve passing to the gray matter at the floor 

 of the ventricle. The restiform tract and its gray matter. 



