330 



NORMAL HISTOLOGY. 



FIG. 353. 



Section of human pineal body : 

 a, a, acini lined and partially 

 filled with epithelium and cal- 

 careous concretions (s) ; f, inter- 

 tubular fibrous tissue. 



FIG. 354. 



mals assumes the characters of a sense-organ to the extent seen in 

 the lower types. 



The adult human pineal body is composed of a number of tu- 

 bular compartments or alveoli, which 

 are separated by septa of connective tissue 

 and lined by polyhedral epithelial cells ; 

 in many places the tubules are almost oc- 

 cluded by epithelium, together with aggre- 

 gations of gritty calcareous matter, the 

 so-called " brain-sand." The brain-sand, 

 or acervulus cerebri, consists of irregu- 

 larly round mammillated or mulberry-form 

 concretions of variable size, composed of 

 animal matter combined with earthy salts 

 (calcium carbonate and phosphate with 

 magnesium and ammonium phosphate). 

 These deposits are not limited to the in- 

 terior of the pineal body, but are encountered on its exterior and on 

 the peduncles, as well as in the choroid plexus and in other parts of 

 the brain-membranes ; the concretions occur 

 at all ages, even before birth, and within the 

 perfectly normal organ. 



Other bodies, the corpora amylacea, 

 occur as round discoidal masses, and exhibit 

 a distinct concentric striation ; they are 

 regarded as amylaceous in nature, since they 

 respond to the tests for such substances, 



staining violet with iodine and sulphuric acid. These bodies are 

 almost constant within both the gray and the white matter consti- 

 tuting the walls of many parts of the brain-cavities ; the olfactory tract 

 is a particularly favorite situation, along this region the amylaceous 

 corpuscles occurring with especial profusion. 



THE SUPRARENAL BODY. 



The close relations of this organ with the nervous system, as 

 evidenced by its early history, the profusion of its nervous elements, 

 and the results of pathological processes, entitle the suprarenal body 

 to place, provisionally at least, within the present chapter. 



The parenchyma of the organ, composed of a peripheral zone, 

 the cortex, and a central area, the medulla, is invested by a fibrous 

 capsule of considerable thickness. From this envelope numerous 

 connective-tissue septa penetrate deeply into the soft cellular 

 substance, which is thus broken up into cylindrical masses. 



The cortex consists of aggregations of irregularly rounded or 



Corpora amylacea from lateral 

 ventricles of human brain. 



