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In the firft place, thofe veflels are remarkable In 
not having any lymphatic glands, that I can difcover, 
in any part of their courfe. In this they agree with 
the turtle, but differ from birds, which have lym- 
phatic glands on the veffels of their necks. 
Secondly, thefe veffels in fifli have no valves, fo 
that it is an eafy matter to fill them contrary to the 
courfe of the lymph. When I firfi; obferved this 
circumftance, I imagined that, by injeding minutely 
thofe veffels, I might difcover their very beginnings, 
and that I might alfo be enabled to determine, whe- 
ther fuch parts as the brain, eye, &c. whofe lympha- 
tics have not been yet feen in any animal, have, or 
have not, fuch veffels. At prefent I am not able to 
determine this matter, but I intend to profecute the 
fubjed. I 
Thirdly, the ladeals in the cod (and I prefume in 
mofl other fifh) are remarkable for having a beautiful 
net-work of veffels between the mufcular and vil- 
lous coat of the inteftines (c). This net-work may 
be filled from the ladeals on the mefentery with the 
leaf!; force imaginable. If mercury be injeded into this 
net- work at one part, it fpreads over the intefline ; 
the communications in the net- work being very nu- 
jnerous : if the intefline be inverted, and the mercury 
fqueezed, it is eafily driven into the fmall veflels of 
the w7// of the internal coat. From thefe veffels 
the mercury can be fqueezed into the cavity of the 
intefline j but not fo eafily as to make it clear whe- 
ther they have, or have not, a valve at their be- 
ginning. In thefe circumflances there is a flrong 
(f) I have feen tins net- work in the turbot, plaice, and cod. 
analogy 
