258 H. E. JORDAN 



city of nerve fibers beyond the basal portion. A few alveoli 

 contain small concretions of brain-sand. 



In none of my specimens have I been able to discover striated 

 muscle fibers, such as first Nicholas ('00) and later Dimitrova 

 ('01) described for the pineal bodies of Bos taurus. Nor do the 

 trabeculae here contain smooth muscle fibers as noted by some 

 investigators for certan forms (e.g., ox; Illing, '10). Nor have I 

 been able to find any evidence of nerve cells which have been 

 reported in certain mammals by several workers (e.g., Hagemann, 

 '71). Moreover, Flesch's statement that pigment clumps are 

 abundant in the pineal bodies of sheep applies only to those of 

 old individuals; and Dimitrova's observations that no brain-sand 

 occurs in the pineal body of sheep is negatived by findings in my 

 preparations where sabulous concretions appear in small amount 

 in the proximal portion of the pineal bodies of yearling sheep, and 

 in large numbers in various forms in old sheep. 



THE PINEAL BODY OF YEARLING SHEEP 



After the first year the pineal gland undergoes a slight decrease 

 in size (6 mm. x 4^ mm.). This is coincident with a decrease in 

 the parenchymal cells and an increase in the connective tissue and 

 neuroglia elements (figs. 9, 10, and 11). The decrease in size is 

 due probably to contraction. The neuroglia fibers appear con- 

 tinuous with the connective tissue at the periphery of the follicles. 

 They are at least very intimately associated or interwoven, in 

 these regions. Corrosive acetic preparations stained with iron- 

 haematoxylin, which stains the neuroglia fibers dark brown or 

 black, combined with Mallory's connective tissue stain, which 

 colors the connective tissue elements blue, shows the point of 

 transition from one to the other. In many preparations these 

 appear to be in absolute continuity. This staining combination 

 reveals clearly the difference in chemical nature between the true 

 connective tissue and the finer neuroglia framework of the paren- 

 chyma. The transition area frequently gives an intermediate 

 color reaction. Only a few of the peripheral cells contain the 

 melanic granules. A few of the central cysts contain acervulus, 

 and there are several spherical areas of dense neuroglia network 

 almost void of cellular elements. 



