F(£TAL NUTRITION: THE PLACENTA 



499 



the cmiiieetive tissue cells undergo acti\e 

 (livisiiin, and they enlarge to form the 

 deeidnal eells (Fig. 15;]). Before the exca- 

 A ation of the "Eikarniner" they are piuli- 

 alily ii(:it found, tliongli Peters descrilied 

 tlie eomniencenient of a decidual change 

 licFoiu that stage. In l\Ierttens' ^ ovum 

 large decidual cells were fomid, many of 

 them fusiform and l)'ing parallel to the 

 surface. Tlie decidual change arises first in 

 the connective tissue cells near the' ovum, 

 and later it extends more deeply in the 

 C(jmpacta. There is no special perivascidai' 

 development as in the ralihit, and nf) endo- 

 thelial pi'oliferation as in the hedgehog and 

 l)at, tliougli tlie latter may occasionally occui' 

 in tnlial pregnancy (Weljster -). 



The capillaries dilate to sinuses, and new 

 vessels are also formed in tlie coiupacta. 

 Many of them are opjened h}' the tr(jpho))last 

 and perhaps hy tlie mononuclear cells, ami 

 grailually more and more Ijleod is efl'nsed 

 into the troplioblastic lacunie. In them it 

 does not clot, the syncytium acting as an 

 endotheliinn, liut at a certain stage the 

 lilood l)eoins to circulate and continues to 

 do So throughout pregnancy. The gland- 

 <liicts are destroyed in tlie necrotic zone. 

 In the underlying compact zone they are 

 found dilated in the serotina and hase of the 

 leHexa, hut even in Ijryce and Teacher's 

 oA'imi the epithelium showed signs of de- 

 generation and des(|uaniation. 



With the formation of the space between 

 the ovum and the decidua, a permanent 

 attachment of the two structures is br<iught 

 about. Tlie development of the villi has 



' Mei'ttens, " Beitriige zur nornialeu und patho- 

 logischen Anatomie dei- menschlichen Placenta," 

 ZeiUvh. f. (iehnrtxh. ii. Hi/mik., vols. xxx. and xxxi., 

 1894-95' 



- Webster, Human Phimdnf;,,,,, Chicago, 1901. 

 Wade and Watson (Jour, of OhstH. and (Jynri: of 

 lirit. Eiiip., 1908) also state that in tubal pregnancy 

 some of the decidual cells are formed from endo- 

 thelium. 





ryp.% 



Pii;. Ifj.S. — Condition of 

 the glands at the Ije- 

 giniiing of ]iregnancv 

 in man (after Kundrat 

 and EngH.niann). 

 (From (^iiaiii'x Aii- 

 atojiti/, Lonyuians. ) 



I, Compact la3'er near 

 free surface of de- 

 cidua ; the glands are 

 here s o m e ^^4l a t e n- 

 larged, but not very 

 tortuous, and the 

 mucous membi'ane is 

 lendered compact by 

 the hyperti'ophy of 

 the in terglandulai' 

 tissue ; •^yJ., spongy 

 layer containing the 

 middle portion of the 

 glands greatly en- 

 laiged and tort;uous, 

 producing a spongy 

 condition in the 

 mucous membrane ; 

 (I, deepest pnrtion of 

 glands, elongated and 

 tortuous, but not 

 much enlarged ; id, 

 musrularis. 



