F(ETAL NUTRITION: THE PLACENTA 363 



motor centre for the ciliary beats. But no movements 

 have yet been observed, and von Lenhossek 1 calls them 

 " stereozilien," or stationary cilia, suggesting that they may 

 help to break down vessel-walls during the burrowing of the 

 syncytium into the serotina. Sometimes they appear not to 

 project free on the surface but to he in the superficial stratum ; 

 then lighter and darker striae alternate, and it is this appearance 

 which has led to the name " striated edge." Bonnet 2 in- 

 geniously remarks that it proves the foetal origin of the syncytium, 

 because, if it were uterine, the free edge would be formed by the 

 bases of maternal cells, and they could not possess a " Biirsten- 

 besatz." The same appearance has been noted in intestinal 

 epithelium, but its significance is unknown. In the placenta 

 Graf v. Spec 3 attributes the appearance to the teasing out of 

 the surface of the protoplasm, and looks on it as evidence of a 

 strong flow of fluid through the syncytium. It has also been 

 suggested that the thin rods may be hollow and act as pores by 

 which nutriment may enter the syncytium, or by which a 

 secretion of the syncytium may pour out in order to prepare the 

 constituents of the maternal blood for their transference to 

 the foetus. 



It is still undecided whether the syncytium possesses 

 amoeboid motility. V. Lenhossek examined a human ovum 

 several minutes after its removal from the uterus and observed, 

 as has already been stated, no ciliary movements ; but he con- 

 sidered it not improbable that the syncytium underwent changes 

 of form. Hofbauer tried unsuccessfully to demonstrate such 

 movements in a specimen examined immediately after its 

 removal. 



The core in young villi consists of a matrix, homogeneous 

 or delicately fibrillated. In it are placed the blood-vessels 

 and connective-tissue corpuscles with long branching processes, 

 which form a network in the matrix, and probably provide a 

 series of lymph-channels. Kastschenko also described special 



1 V. Lenhossek, Verhandl. d. anal. Kongresses in Halle, 1902. See 

 Centralbl. f. Gynak., 1904, Nr. 7. 



2 Bonnet, " tJber Syncytien," &c., Monatsschr. /. Geburteh. u. Oynnk., 

 vol. xviii., 1903. 



3 Graf v. Spee, "Neue Beobachtungen iiber sehr friihe Entwickelungs- 

 stufen des menschlichen Eies," Arch. f. Anat. u. Phya., anat. Abth., 1896. 



