THE PINEAL BODY OF THE SHEEP 259 



PINEAL BODIES OF OLD SHEEP 



Pineal bodies of sheep of the third year are characterized by 

 several degenerative changes; viz.: (1) great increase in the con- 

 nective tissue elements; (2) large and numerous areas of dense 

 neuroglia network free of cells ; (3) areas of apparently coagulated 

 fluid matter; (4) large clumps of intercellular pigment granules 

 in the peripheral portion; (5) comparative rarity of spherical 

 inter-neuroglia cells. The histologic characteristics point to a 

 cessation of active function and to the onset of degeneration. 

 Judging from the standpoint of histologic and cytologic features, 

 the assumed specific function of the pineal gland is important, 

 perhaps essential, only during the first year of life. 



GENERAL 



Regarding the question as to whether the connective tissue 

 framework of the pineal body is in the form of complete or incom- 

 plete anastomosing septa (trabeculae), the evidence in sheep 

 favors the conclusion arrived at by Dimitrova in the ox by the 

 digestion method, viz.: that it consists of trabeculae. This is 

 more particularly true of the main pial extensions as is clearly 

 demonstrated in transverse sections which are circular or oblong 

 in outline (fig. 6). On the other hand, the terminal extensions 

 seem more of the character of reticular sheets of tissue or trabecu- 

 lar network. Studnicka's ('05) suggestion, that possibly in the 

 earlier stages of development, the connective tissue framework of 

 mammalian pineal bodies may actually have the form of septa, 

 as in adult birds, does not express the actual condition in the 

 sheep. Here the earliest pial extensions, as noted for the 10 cm. 

 stage of development, have the character of broad trabeculae. 



The blood-vessels follow the ramifications of the pial extensions. 

 There is no question of precedence. The septa are already vas- 

 cular at the period of first invasion; and the blood-vessels grow 

 as the trabeculae lengthen. The blood-supply comes from the 

 pial vessels which are in union with the blood-vessels of the tela 

 choroidea anteriorly. An ependymal membrane continuous with 

 the latter covers the antero-dorsal aspect of the pineal body. The 



