216 NORMAL HISTOLOGY. 



being found, as a rule, in the anterior cornua. They 

 are arranged in irregular groups in different parts 

 of the cord. 



The connective-tissue elements of the gray mat- 

 ter consists of a delicate neuroglia framework, simi- 

 lar, in most respects, to that supporting the nerve- 

 fibres between the coarser septa of the white 

 substance. In the hinder portions of the posterior 

 cornua there is a circumscribed area, which, in the 

 fresh cord, has a peculiar gelatinous appearance, 

 and is called the substantia gelatinosa of Rolando; 

 in this we find comparatively few nerve-elements 

 and much connective tissue. The limitations of 

 this manual will not permit us to consider more in 

 detail what is known of the course of the nerve- 

 fibres through the cord, and the more exact rela- 

 tions to the ganglion-cells. 



The blood-vessels enter the cord from the pia, 

 along the septa which the latter sends into the 

 organ, and ramify in its substance, the capillary 

 plexuses being denser in the gray than in the white 

 matter. 



THE BRAIN. 



In this organ also we have gray and white mat- 

 ter ; but they are arranged in a much more compli- 

 cated manner than in the spinal cord, the grouping 

 being far too intricate for consideration here. The 

 collections of gray matter are variously associated 



