GO 



EXPERIMENTAL STUDIES ON FETAL ABSORPTION. 



Reitz, \\ "., 1868. Ueber die passiven Wanderungen von 

 Zinnoberkornchen durch den thierischen Organ- 

 ismus. Berichte der Wiener Akad. math. 

 naturw. Classe, vol. 57 (2), p. 8. 



Schlecht, H., 1007. Experimentelle Untersuchungen 

 liber die Resorption unci die Ausscheidung des 

 Lithionkarmins unter physiol. u. patiiol. Bedin- 

 gungen. Ziegler's Beitrage, vol. 40, p. 312. 



Schoenfeld, H., 1903. Contribution a I'etude de la 

 fixation de l'ceuf des mammiferes dans la cavity 

 uterine, et des premiers stades de la plaeentation. 

 Arch, de biol., vol. 19, p. 701. 



Weed, L. H., 1917. The development of the cerebro- 

 spinal spares in pig and in man. Contributions 

 to Embryology, vol. 5, Carnegie Inst. Wash. 

 Pub. No. 225. 



Wislocki, G. B., 1916. The staining of amphibian 

 larvae with benzidine dyes, with especial reference 

 to the behavior of the lymphatic epithelium. 

 Amer. Jour. Physiol., vol. 42, p. 12.V 



Zuntz, N., 1885. Ueber die Quelle und Bedeutung des 

 Fruchtwassers. Pfliiger's Arch., vol. 6, p. 548. 



Zweifel, 1875. Untersuchungen iiber das Meconium 

 Arch. f. Gyn., vol. 7, p. 474. 



EXPLANATION OF PLATES. 



b. b. Brown border. 



ch. Chorion. 



ch. ep. Chorionic epithelium. 



e. I. Ectodermal lamella'. 



Key to Leoends 



endo. Endothelium. 



e. v. Endodermal villi. 



/. b. v. Fetal blood-vessel. 



(j. c. Giant cell. 



Plate 1. 



in. I). i>. Maternal blood-vessel. 



pi. Placenta. 



r. b. c. Red blood-cell. 



Fig. 1. Gross appearance of the placenta and fetal membranes from the uterus, 12 hours after injection of a vital 



stain into the amniotic cavity. Note the prominent omphalo-mesenteric vessels. 

 Fig. 2. Gross appearance of a guinea-pig fetus with the amnion opened 36 hours after injection of trypan-blue into 



the amniotic cavity. The omphalo-mesenteric vessels can be seen in the wall of the amniotic sac. 

 Fio. 3. Guinea-pig fetus, nearly full term, after injection of potassium ferrocyanide and iron ammonium citrate 



into the amniotic cavity. The fetus was killed 30 minutes after injection and immersed in acid formalin. 



Notice the deep Prussian-blue stain in the lungs and trachea. The stomach contents also were blue. The 



kidneys are slightly stained. 

 Fig. 4. Sagittal section of guinea-pig, measuring 36 mm., 48 hours after the introduction of trypan-blue into the 



amniotic cavity. Note that the central nervous system remains unstained. 

 Fig. 5. Appearance of the placenta and membranes of a guinea-pig fetus after a single injection of trypan-blue into 



the maternal circulation. Notice the endodermal villi which are deeply stained, e. v. endodermal villi 



Plate 2. 



Fig. <>. Precipitation of Prussian blue in the omphalo-mesenteric vessels by immersion of the fetal membranes 

 in acid formalin 30 minutes after the injection of 1 per cent potassium ferrocyanide and iron ammonium 

 citrate into the amniotic cavity, demonstrating the escape of solutions from the amniotic sac into the fetal 

 circulation. 



Fio. 7. Kidney of guinea-pig fetus measuring 36 mm., showing trypan-blue in the convoluted tubules 72 hours 

 after the injection of the dye into the amniotic cavity. Notice that the glomeruli are unstained. 



Fig. 8. Section of the umbilical cord of a guinea-pig fetus measuring 42 mm., showing vitally stained mucoid con- 

 nective-tissue cells, 24 hours after injection of trypan-blue into amniotic cavity. V., lumen of umbilical vein. 



Fig. 9. Section of amniotic membrane of guinea-pig fetus measuring 41 mm., showing absorption of trypan-blue, 

 24 hours after injection of the dye into the amniotic cavity. 



Plate 3. 



Fin. 10. Section of the endodermal villi, the modified remains of the "inverted yolk-sac," heavily laden with pigment 



after repeated injection of a colloidal dye into the maternal circulation. 

 Fig. 11. Wall of the "inverted yolk-sac," showing the endodermal cells as they appear 24 hours after an injection of 



trypan-blue into the amniotic cavity. Fresh membrane slightly eounterstained with alum carmine. 

 Fin. 12. Section through placenta of guinea-pig fetus measuring 40 mm., showing a vitally stained macrophage 26 



hours after injection of trypan-blue into the amniotic cavity'. 



Plate 4. 



I'm. 13. Cat fetus, measuring 6.8 cm., surrounded by unruptured membranes, showing the coloration of the placenta 

 and chorion after repeated injection of trypan-blue into the maternal circulation. Note that the chorion 

 over the poles of the fetus is unstained. The allantoic and amniotic fluids do not contain a trace of dye 

 and the fetus is unstained. 



Fin. 14. Placenta of cat, nearly full term, after repeated injection of trypan-blue into the maternal blood stream, 

 showing the distribution of dye in the chorionic epithelium. 



Fin. 15. Placenta of a vitally stained cat, nearly full term, showing several multimiclear giant cells of the chorionic 

 ectoderm filled with particles of trypan-blue. 



Fin. 16. Section of the "brown border" of the placenta of a cat, nearly full term, showing the absorption of erythro- 

 cytes and of trypan-blue by the chorionic epithelium. 



