Mr. Home’s Experiments on Fluids , &c. 
1% 
In this and the following experiments the infusion of rhu- 
barb was employed in preference to the prussiate of potash, in 
consequence of its having been found in those I formerly 
made, that one drop of tincture of rhubarb could be detected in 
half an ounce of serum, and nothing less than a quarter of a 
grain of prussiate of potash in the same quantity could be 
made to strike a blue colour when the test was added. 
Experime?it s. 
The experiment was repeated upon a dog. In this I was 
assisted by Mr. Brodie, Mr. William Brande, Mr. Clift, 
and Mr. Gatcombe. After the thoracic duct had been secured, 
two ounces of strong infusion of rhubarb were injected into 
the stomach, and in an hour the dog was killed. The urine 
in the bladder, on the addition of potash, became deeply tinged 
with rhubarb. The bile in the gall bladder, by a similar test, 
was found to contain rhubarb. The lacteal vessels in several 
parts of the mesentery had burst, and chyle was extravasated 
into the cellular membrane ; the thoracic duct had given way 
in the lower part of the posterior mediastinum, and chyle was 
extravasated. Above the ruptured part the thoracic duct was 
much distended with chyle ; it was readily traced to the liga- 
ture, by which it was completely secured. 
These experiments appeared to establish the fact, that the 
thoracic duct was not the channel through which the infusion 
of rhubarb was conveyed to the circulation of the blood, and 
it now became easy to ascertain, whether it passed through the 
spleen, by extirpating that organ, and repeating the last expe« 
riment. 
MDCCCXI. 
y 
