6 Sir Everard Home’s farther investigation 
soft part consisted only of about one-fourth of lvmph globules, 
the rest being red globules which had lost their colour. 
The structure of such tumors is nearly allied to that of 
the layers in an aneurism. That these layers never become 
vascular, arises from the aeriform matter, evolved at the time 
that the blood coagulates, readily escaping into the circu- 
lating blood with which it is in contact. 
To ascertain whether the proportion of aeriform matter in 
the blood is liable to vary, as well as to determine its nature, 
a very buffy coagulum was placed in the receiver of an air 
pump, with a syphon passing from the vessel containing it into 
a bottle filled with barytes water. The pump was worked, and 
the gas only came over in single bubbles, which occasioned a 
precipitation of carbonate of barytes. From a less buffy coagu- 
lum the gas came over in several bubbles at a time. When 
there was no buff, the gas was abundant, and the precipitation 
copious. To ascertain whether this gas is produced in the 
process of digestion, a pauper from one of our work-houses, 
an hour after eating a hearty dinner and drinking a pint of 
porter, was bled at the arm to six ounces. The coagulum 
was tested in the same manner as the others in the air pump, 
and at the same distance of time from that at which the blood 
was drawn, the gas passed through the syphon in a torrent, 
and there was a proportionate precipitation. 
Carbonic acid gas, Professor Brande finds to be commonly 
met with in the urine ; but in greater quantity immediately 
after a full meal. 
The source from whence the carbonic acid gas is supplied, 
having been thus determined, an attempt was made to trace 
