fetus and its embryonic membranes. 6 A year later in ISIS, 

 Bo j anus considered the membranes of the human fetus. 7 in 

 that work he is considered to have corrected the main mistake 

 in the description of the sloughed-off membranes, which 

 remained from Hunter's time. Bo j anus showed that the ovum, 

 going out from the Fallopian tube, passes between the wall 

 of the uterus and the sloughed-off membrane. By increasing 

 in size, it separates the membrane from the uterine wall to 

 the extent that the hillock which is covered with the sloughed- 

 off membrane protrudes increasingly into its cavity. In the 

 place where the fertilized ovum contacts the uterine wall, the 

 maternal placenta forms. In the same place, the uterus forms 

 a new sloughed-off membrane [Bojanus calls it decidua 

 serotina) , in which the vessels grow from the chorion and 

 the maternal placenta. And thus, at the beginning the decidua 

 bends through the fertilized ovum and covers it only in those 

 places where it is not in contact with the uterine wall. The 

 end of the ovum appears to be surrounded with the sloughed-off 

 membrane. Schematic illustrations (Figure 20], further 

 elucidate the description. 



In the same ISIS article is a small note,** addressed 

 to the editor of this journal, L. Oken. There Bo j anus cited 

 Oken's unjustified attack and proposed that Oken should more 

 accurately formulate his point of view on the nature of the 

 sloughed-off membrane. Bojanus' dissatisfaction is entirely 

 justified, because against Bojanus' accurate observations 

 Oken had opposed only the dim ideas of Naturphilosophie. 



A year later Bojanus published a work in which, by 

 extending his previous material, he gave a description of 

 the relationship of the umbilical sac to the membranes in 

 the hare. 9 



Bojanus, "Observatio anatomica de foetu canino 24 dierum 



ejusdem velamentis," NOVA ACTA ACAD. LEOPOLD . -CAROL . , 



10 (1820) , p. 139. 



Bojanus, "Ein Wort iiber das Vernal tniss der membrana 



decidua und decidua reflexa zum Ei de menscher lichen 



Embryo," ISIS (1821), pp. 268 - 271. 



Bojanus, "Anfrage und Bitte wegen der membrana decidua," 



ISIS (1821) , p. 1174. 



Bojanus, "Uber die Darmblase des Haasef oetus , " ISIS (1822) , 



pp. 1228 - 1230. 



234 



