34 
ON THE MESENTERIC VEINS. 
then, from the diminished quantity of pure chyle being made, 
the function of absorption by the lacteal vessels, no doubt, 
becomes much less than is natural, and the entire system 
very soon suffers from direct debility, the result, I should say, 
of imperfect chylification. While, in addition to this, from the 
very large or unnecessary quantity of watery fluid which in 
wet seasons is always taken in with food, the mesenteric veins, 
no doubt, for a time attempt to remove it by a process of ab¬ 
sorption in the natural way; but in consequence of this undue 
quantity of watery fluid being compelled to pass from the mesen¬ 
teric veins through the substance of the liver^ a chronic inflam¬ 
mation of that very important organ is the ultimate and not dis¬ 
tant result; and hence follows dropsy, frequently diarrhoea, and, 
at length, death. 
In such cases as these, the biliary ducts after death are very 
frequently found to contain a great number of flat worms, com¬ 
monly called flukes. These by many are considered, in addition 
to the wetness of the seasons, as the cause of the disease of the 
liver. I am not inclined to believe that they are of any service ; 
but I should rather consider them as the effect than as the cause 
of disease ; for it is a well known fact, that almost all animals, 
when become more or less sickly or unhealthy, or approaching 
to a state of disease, are found to generate animalculce in 
various parts of the interior of their bodies, and which are 
seen in the form of intestinal worms, &c. 
As I have, 1 am afraid, departed too far from the subject, I 
shall now again return to the function of absorption by the ex¬ 
treme radicles of the mesenteric veins. Dr. Copland, in his Ap¬ 
pendix to the second edition of Richerand’s Physiology, 1829, in 
treating on the function of absorption from the digestive canal, 
states, that from the experiments of Tiedemann and Gmelin 
on absorption, the lacteals take up the digested and dissolved 
portions of alimentary substances, and convey them, as chyle, 
through the thoracic duct to the bloodvessels; but as odori¬ 
ferous, colouring, and some saline substances are not absorb¬ 
ed by them, and yet are found in the blood of the vena portae, 
and in secreted fluids, it necessarily follows, that there must be 
some other way than the thoracic duct by which they pass into 
the blood. 
The following are the chief suppositions which have been 
offered in explanation of the facts. Either all the lacteals do 
not enter the thoracic duct, and a part of them join the veins 
which form the vena portae, and thus transmit their contents into 
the blood of the vena portae, or substances pass directly from the 
stomach and intestinal canal into the veins; or, finally, both of 
these suppositions may be true. 
