10 HAND-BOOK OF PHYSIOLOGY. 



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 dis- 

 coloration 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. 



PITUITAKY BODY. 



This body is a small reddish-grey 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 toward 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 granular sub- 

 stance. The vesicles are enclosed by connective tissue rich in capil- 

 laries. 



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 

 (Fig. 327, g). 



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

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

 cal layer, analogous in structure to the anterior lobe of the pituitary body; 

 and (2) An inner central layer, wholly nervous. The cortical layer con- 

 sists of a number of closed follicles, containing (a) cells of variable shape, 

 rounded, elongated, or stellate; (b) fusiform cells. There is also present 

 a gritty matter (acervulus cerebri), consisting of round particles aggre- 

 gated into small masses. The central substance consists of white and grey 

 matter. The blood-vessels are small, and form a very delicate capillary 

 plexus. 



Function. Of this there is nothing known. 



FUNCTIONS OF THE VASCULAR GLANDS IN GENERAL. 



The opinion that the vascular glands serve for the higher organization 

 of the blood, is supported by their being all especially active in the dis- 

 charge of their functions during foetal life and childhood, when, for the 



