( 840 ) 
Some deny a TJrimry Membrane to a Humane Fittus^ 
becaufe they fuppofe the Vrachus to be impervious, and 
that therefore there would be no paffage for the Urine, 
cT^^'^th^ confequently no need of an Allmois. (m) Needham in- 
cap. 7th. deed fays that he could never find any fign of a Cavity 
in the IJrdchus^ yet is of opinion, that by blowing from 
the Bladdery the Air might be forced through a Humane 
ZfrachHs^as eafily as he has often done it through that of 
a Whelp, I don't underftand why Dr Needham^ and f «) 
^"^1^ ^"^®y others fliould infift fo much upon an apparent Cavity 
caVsi* ^be TJrachus^ or expeft that air fliould neceflarily pafs 
Maurieau thfough it upon blowing, and think that otherwife it 
cap! 4th cannot be fit for the affigned Office ^fince many Bodies, 
as Membranes, &c. will not admit Air, dv. yet let Wa- 
ter pafs freely through them. It will not feem ftrange, 
that Water fliould pafs through the fubftance of the 
Urachns, it we confider that the Cavity of the Drachus 
to the Navel IS open5as appears by Inflation, or Injedions, 
fto fay nothing of thofe who are mentioned to have 
Lib^^ca* ^^^^ Water by the ( o) Navel) and that the refl: of the 
j '^^^Urachus is pervious, tho* not plainly hollow, (the Urine 
Senn. Lib. rather foaking gently, than running through its more 
partS.fea.ft^^^^ Tubes ) may be gathered from hence, ifl:. That 
idcap.io. the fubn:ance of the Urachus, ( as well as the Cavity of 
Lfb^^sth Allantois) is always found turgid with a Liquor, that 
Queft. 17. in colour, tafl:e and fmell, feems Urinous. 2dly, That 
Cnce the Mucous Coat of the Inteftines is demonftrated to 
be vafcular hy Mx Leeuwenhoeck-, therefore the Mucous 
fubflrance of the Urachus may alfo be Vafcular.* ^dly. 
That Urine may as eafily ouze through thefe Mucous 
Veflels, as other fluids run through Vafcular Cartilages^ 
and Bones ^ &c. or the Chyle into I^(Je^//, whofe Orifices 
Vol.id as (p) Leeuwenhoeck obferves, will fcarce admit of Parti- 
pa^^i 'f^' cles fo big as the iooocoqcco part of a grain of fand ) 
the great Cavity of the Intefliines being open at the fame 
time 5 pr as eafily as grofler parts of the Semen pafs the 
Tubes 
