392 HANDBOOK: or PHYSIOLOGY. 



and size, poor in fat, and occasionally branched; the nerves run through 

 the cortical substance, and anastomose over the medullary portion. 



Function. Of the function of the supra-renal bodies, nothing can be 

 definitely stated, but they are in all probability connected with the 

 lymphatic system. 



Addison's Disease. The collection of large numbers of cases in 

 which the supra-renal capsules have been diseased, has demonstrated the 

 very close relation subsisting between disease of those organs and brown 

 discoloration of the skin (Addison's disease); but the explanation of this 

 relation is still involved in obscurity, and consequently does not aid 

 much in determining the functions of the supra-renal capsules. 



Pituitary Body. 



This body is a small reddish-gray mass, occupying the sella turcica 

 of the sphenoid bone. 



Structure. It consists of two lobes a small posterior one, consist- 

 ing of nervous tissue; an anterior larger one, resembling the thyroid in 

 structure. A canal lined with flattened or with ciliated epithelium, 

 passes through the anterior lobe; it is connected with the infundibulum. 

 The gland spaces are oval, nearly round at the periphery, spherical to- 

 wards the centre of the organ; they are filled with nucleated cells of 

 various sizes and shapes not unlike ganglion cells, collected together into 

 rounded masses, filling the vesicles, and contained in a semi-fluid gran- 

 ular substance. The vesicles are inclosed by connective tissue, rich in 

 capillaries. 



Function. Nothing is known of the function of the pituitary body. 



Pineal Gland. 



This gland, which is a small reddish body, is placed beneath the back 

 part of the corpus callosum, and rests upon the corpora quadrigemina. 



Structure. It contains a central cavity lined with ciliated epithe- 

 lium. The gland substance proper is divisible into (1.) An outer cor- 

 tical layer, analogous in structure to the anterior lobe of the pituitary 

 body; and (2.) An inner central layer, wholly nervous. The cortical 

 layer consists of a number of closed follicles, containing (a) cells of va- 

 riable shape, rounded, elongated, or stellate; (#) fusiform cells. There 

 is also present a gritty matter (acervulus cerebri), consisting of round 

 particles aggregated into small masses. The central substance consists 

 of white and gray matter. The blood-vessels are small, and form a very 

 delicate capillary plexus. 



Function. Of this there is nothing known. 



