"7 "7 



UMBILICAL VESSELS. Sect. III. I. 2, 3. 



fible many days before the flower opens, and in confequence before 

 ley are impregnated, as obferved by Spallanzani. 

 2. The ep-es of birds contain a bas: of air at their broad end for the 



purpofe of oxygenating the blood of the chick. In this one circi 

 ftance the feeds of plants feem to differ from the esr^s of birds, as 



too 



they contain no air-ba 



i3» 



though 



o 



probable they may 



fpawn of fifli, which I fuppofe poflefs no included 



When th 



feeds fall on the ground in their natural flate of growth, or are buried 



beneath the foil, which has recently been turned 



and th 



much air in its 



ft 



their coats d 



not 



dry like the fhells of eggs during incubat 



but immed 



ely become moift membran 



like the external membrane of 



fpawn of fifli immerfed in water, and in confequence can admit th 

 oxygenation of the air through them to an adapted fet of art( 

 their internal furface, according to the curious obfervations 



on 



of D 



Prieftley on the oxygenation of the blood by the air through the moift 

 membranes of the lungs. 



It (hould be here obferved, that many feeds, before they fall on the 



h 



irioift earth, are included 



baff of 



o 



thofe of the ftaphyl 



bladder-nut ; of the phyfalis alhekengl, winter-cherry ; of colutea, 

 bladder-fenna ; in the pods of peas and beans ; in the cells furround- 

 ing the feeds of apples and pears ; and in the receptacle 6f ketmia, 

 which prpbably ferves to oxygenate the blood of the infant feed, which 



thefe plants may thus be of forwarder growth, before it is ftied upon 



the foil. 



3. There exifts a feries of glands, and their du6ls, improperly 

 called umbilical veffels by fome writers, which fupplies the feed with 

 nouriftiment from the parent plant, fo long as it adheres to the ova- 

 rium of its mother, as the veflels by which a pea adheres to the pod, in 

 which it is included ; in fruits and nuts, where the kernel is covered 

 with a ftone or fti^ll, a long cord of veffels paffes into the bottom of the 



ftone or ihell, and rifmg to the top bends round the lobes of the ker- 

 nel 



I 



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