[ 2 *7 ] 
Received Oftober 3, 1768. 
XXXIV. An Account of the Lymphatic Syfletn 
in Birds ; by Mr. William Hewfon, Reader 
in Anatomy : In a Letter to William 
Hunter, M. D. F. R. S. and by hi?n com - 
inunicated to the Society . 
S I R, 
Read December 8, T T A V I N G been fo fortunate, in a ! 
1768. J~JL feriesof experiments made with 
that view, as to trace out the lymphatic fyftem in 
birds, I have ventured to offer the following account 
of it to you, in order to be prefented, if you think 
proper, to the Royal Society ; and, I flatter myfelf, 
this difcovery will be looked upon as fome acquifltion 
to phyfiology. 
The lymphatic fyffem has been fuppofed to be 
wanting in birds ; and abforption in that kind of ani- 
mals to be carried on by branches of the common 
veins. Phyfiologifts were led into this opinion by 
obferving, that though the lacSteals and mefenteric 
glands were eafily feen even in the fmalleff quadruped, 
yet the mod acute anatomiffs had not been able to 
find in any bird the leafl appearance either of thofe 
veffels or glands. The difficulty of difeovering the 
ladteals in birds was, no doubt, principally owing 
to the tranfparency, or want of colour, in the fluid 
which they contain. In quadrupeds the ladteals are 
eafily found, as they are filled with chyle, which is 
moftly opaque and white; whereas, in birds, the chyle 
is as pellucid and colou riels as the veffels themfelves. 
Vgl. LVIII. F f The 
