Mr. Home’s Experiments on Fluids, &c. iGg 
pleteiy to establish the fact, that the rhubarb did not pass 
through the thoracic duct, and therefore must have got into 
the circulation of the blood by some other channel. They 
likewise completely overturn the opinion I had adopted of 
the spleen being the medium by which the rhubarb had been 
conveyed, and show that the spleen answers some other pur- 
poses in the animal economy. 
The rhubarb found in the spleen does not arrive there be- 
fore it enters the circulation, it is therefore most probably after- 
wards deposited in the cells in the form of a secretion. That 
the rhubarb goes into the circulation is proved by my former 
experiments, in which it was detected in the splenic vein.. 
The prussiate of potash is hardly to be discovered in the blood 
of a living animal, since the proportion which strikes a blue 
colour on the addition of solution of iron, is greater than the 
circulating fluids can be expected to contain at any one time, 
as it goes off by the secretions nearly as fast as it is received 
into the blood vessels. In a moderately sized ass more than 
two drams must be dissolved in the blood before its presence 
there can be detected. 
That the fluid contained in the cells of the spleen is 
secreted there, is rendered highly probable, since it is most 
abundant while the digestive organs are employed, and 
scarcely at all met with when the animal has been sometime 
without food. The great objection to this opinion is, there being 
no excretory duct but the lymphatic vessels of the spleen ; these 
however are both larger and more numerous than in any other 
organ ; they are found in the ass to form one common trunk* 
which opens into a large gland on the side of the thoracic 
duct, just above the receptaculum chyii; a nd when the quick- 
