DIGESTION VISIBLE TO THE EYE. 
389 
from the stomach, and the vial was replaced in the bath. Di- 
gestion, which had previously ceased, was now resumed, and went 
on as steadily as if it had not been interrupted; thus shewing, 
in a striking manner, the impropriety of exceeding in our meals 
the quantity for which alone a sufficiency of gastric juice can be 
provided. 
“At the end of twenty-four hours, the three portions were 
examined. That contained in the warm juice was completely 
dissolved, and presented the usual appearances. The portions 
contained in the cold juice and in the cold water very much 
resembled each other, and exhibited no appearance of chyme 
whatever. They were macerated or softened, but not digested. 
These experiments, and others of a similar nature, shew clearly 
that a temperature equal to ordinary blood-heat is requisite for 
chymification. 
“ To make sure that it was the low temperature alone which 
prevented the occurrence of digestion in the experiment detailed. 
Dr. Beaumont now placed the vial containing the meat which 
had been exposed without effect for twenty hours to the action 
of the cold gastric juice, on a water-bath at the ordinary blood- 
heat. In a very short time, * digestion commenced, and ad- 
vanced regularly as in the other parcels/ The same results were 
always obtained from a repetition of these experiments, so that 
they may be held as perfectly conclusive in establishing the 
essentiality of heat to the digestive process. 
“ Thirdly. — The necessity of gentle and continued agitation 
for the accomplishment of digestion is so obvious from the 
preceding exposition, that it requires no direct experiments to 
establish it. When portions of meat were suspended in the 
stomach by a string so short as to prevent them from being fully 
subjected to the motion already described as always going on 
during digestion, the action of the gastric juice was confined 
almost entirely to their surface, and a longer time was con- 
sequently required for their solution than when they were left at 
liberty. In the like manner, when meat out of the stomach was 
placed in a vial containing gastric juice, its solution was uniformly 
accelerated by gentle agitation, which acted simply by removing 
the coating of chyme as it formed on the surface, and thus 
affording to the gastric fluid an easier access to the undigested 
portions below. Accordingly, when in one of Dr. Beaumont’s 
experiments two ounces of unmasticated roasted beef were 
introduced through the external aperture into the stomach, and 
held by a string, only one-half of it was digested in four hours, 
evidently from the want of mastication confining the action of 
the gastric juice to the surface of the mass, and because the 
