168 FREDERICK TILNEY AND LUTHER F. WARREN 



manner: 1) basophilic granules in the nuclei; 2) the latter evac- 

 uated into cytoplasm. This process goes on during the entire 

 life of the individual even into old age. 



Biondi ('12) 49 calls attention to the finding of Constantini 71 

 and Galeotti 140 of acidophiles in the pineal body. Biondi made 

 a special study for mitochondria by the method of Regand. 

 He was able to demonstrate small granules which he thinks 

 must be regarded as mitochondria. This he cites as evidence 

 of the secretory nature of the epiphysis. He calls attention to 

 the fact, however, that Nageotte 281 and Mawas 263 have both 

 stated that neuroglia cells also contain mitochondria. 



Jordan, ('II) 197 following the histogenesis of the pineal body 

 of the sheep, studied six stages from 5 cm. to 21 cm., also of the 

 eight months' lamb, yearling, and old sheep. He found no 

 muscle fibers. Between birth and the first year the pineal body 

 increases fivefold in size. In the fetus there are blind alveoli 

 and the organ is definitely lobulated by ingrowths from the pia. 

 Parenchymal cells form these alveoli. Vascular follicles are 

 abundant. The parenchyma consists of a more or less dif- 

 ferentiated ependyma. After the first year there are signs of 

 local degeneration manifesting themselves as an increase in con- 

 nective tissue, neuroglia, brain sand, clumps of pigment granules, 

 and a decrease of parenchymal cells. The entire pineal body 

 decreases in size after the first year. He concludes that there 

 is no cytologic evidence in favor of the secretory function of the 

 sheep's pineal body. He points out, however, that the general 

 structure of the epiphysis, including its lobulation, its connec- 

 tive tissue framework, its parenchymal follicles, blind alveoli, 

 perivascular lymph spaces, great vascularity, and presence of 

 cytoplasmic granules, is indicative of a glandular function of 

 internal secretion. He interprets the cysts which appear in the 

 pineal body and the melanic cytoplasmic granules as probably 

 having an ancestral significance. In Jordan's opinion, if the 

 pineal body subserves any important function at all, this is 

 true only of the first eight months of postnatal life. 



Jordan 198 in the same year, studying the pineal body in the 

 opossum, states that the organ in this species has two forms: 



