924 



SPERM, OVA, AND PREGNANCY 



though the findings of Luse (1958), Luse, 

 Davies and Smith (1959), Luse, Davies and 

 Clark (1959) suggest that it is absorbed 

 lipid. Further discussion of the lipids of the 

 yolk sac was given in the section on yolk 

 sac placentation. 



In placentas of two species of shrews 

 {Blarina brevicauda and Sorex fiimeus) 

 Wimsatt and Wislocki (1947) described nu- 

 merous coarse lipid droplets in the colum- 

 nar trophoblastic epithelium forming the 

 chorionic membrane. These droplets are su- 

 danophilic and birefringent, exhibit green- 

 ish fluorescence, and give an intense 

 reaction with Schiff's reagent. In the cho- 

 rio-allantoic placenta, minute sudanophilic 

 particles are observed in the placental tra- 

 becule, but birefringence and fluorescence 

 are not evident and Schiff's reaction is 

 feeble. 



In the placenta of the bat {Myotis luci- 

 fugus lucifugus) Wimsatt (1948) observed 

 sudanophilic lipids in nearly all placental 

 constituents, but only those present in the 

 columnar trophoblastic cells of the mem- 

 branous chorion were birefringent, emitted 

 a greenish-yellow fluorescence, and gave 

 positive phenylhydrazine, Schiff's and Lie- 

 bermann-Burchardt reactions. With respect 

 to these reactions, it is apparent that the 

 membranous chorion of shrews and bats is 

 similar. 



In the placenta of the Virginia deer {Odo- 

 coileus virginiayms borealis) in midgesta- 

 tion, lipid droplets which are birefringent 

 and give an Ashbel-Seligman reaction are 



present in a layer of epithelium lining the 

 maternal crypts of the placentomas (Wis- 

 locki, 1952) . A further interesting feature of 

 the deer's placenta is an intense reaction for 

 lipids (sudanophilia, birefringence, positive 

 Ashbel-Seligman carbonyl reaction) in the 

 withered, degenerating peripheral ends of 

 the maternal septa. This reactive material 

 is evidently attributable to degeneration 

 of a portion of the epithelium covering the 

 maternal septa. 



In the sheep, the epithelial layer clothing 

 the maternal septa consists of syncytial tro- 

 phoblast derived from the chorionic villi 

 (Wimsatt, 1950; Amoroso, 1951, 1952). Al- 

 though it has not been investigated, the epi- 

 thelium lining of the maternal crypts of the 

 deer's placenta may also be of fetal origin. 

 In the sheep, Wimsatt (1951) remarks 

 briefly that lipid droplets, which are bire- 

 fringent and give positive Baker's acid- 

 hematein and Liebermann-Burchardt reac- 

 tions, are present in the columnar 

 trophoblastic cells, but no mention is made 

 of the reaction of the syncytial tro]ihoblast 

 lining the maternal crypts. 



In view of the localization of these vari- 

 ous lipid reactions in some part of the tro- 

 phoblast, results obtained in the placenta of 

 a pig (17 cm. crown to rump length) are an 

 interesting exception (Wislocki, 1952). At 

 this period of gestation, lipids are not en- 

 countered in the chorionic epithelium, ex- 

 cept phospholipids of mitochondria which 

 are demonstrable by means of sudan black 

 B (Fig. 15.15) and Baker's acid hematein 



Plate 15. XII 



Fig. 15.50. Human placental labyrinth at full term, .-stained by the periodic acid-Schiff 

 (PAS) method after exposure of the section to saliva. Zenker's acetic acid fixative. The walls 

 of the sinusoidal fetal capillaries and the (reticular) basement membrane upon which the 

 syncytium rests are deeply stained. The outer zone of the syncytium is also noticeably 

 stained. Although many of the capillaries deeply indent the syncytium producing so-called 

 "syncytial" or "epithelial plates," a narrow rim of syncytium and the PAS-stained wall of 

 the subjacent capillary always intervene between the intervillous space and the lumen of 

 the capillary. Compare with Figures 15.14. 15.19, 15.25, and 15.41. X 280. 



Fig. 15.51. Degenerate placental villi at 2 months of gestation, illustrating their intense 

 metachromatic staining with toluidin blue. Basic lead acetate fixative. Compare with Figure 

 15.57. X 240. (Wislocki and Dempsey, 1948.) 



Fig. 15.52. Human decidua vera at 2'/2 months of gestation, stained by the PAS method. 

 Rossman's fixative. Observe the pronounced staining of ground substance encapsulating the 

 poorlv stained decidual cells. Two arterioles are visible near the center of the figure. Compare 

 with Figures 15.53 and 15.58 which illustrate decidua stained by other means. X 240. (Wislocki 

 and Dempsey, 1948.) 



Fig. 15.53. Human decidua vera at 4 months of gestation, .showing the acid phosphatase 

 reaction of the decidual cells. Gomori's method, using glycerophosphate as substrate at pH 

 47. X 240. (Wislocki and Dempsey, 1948.) 



