238 Origin and Destiny of Cholesterol in the Anomal Organism. 
difficult to perform, as they would involve the artificial digestion of large 
quantities of material, for it has been shown that it is impossible to extract 
the whole of the fatty matter from meat without such digestion. Further- 
more, the quantities would probably have been variable. In the two 
experiments quoted, however, the cholesterol found would only have meant, 
in the case of beef and mutton, a content of 0-008 per cent., and in the case 
of horseflesh of 0°015 per cent. 
In experiment (f), with an oatmeal diet, we found only 0:1 gramme of 
cholesterol. Whether oatmeal contains any traces of cholesterol we cannot 
say, but on extracting three days’ diet we were unable to recognise any in the 
unsaponifiable residue. Taking this 0:1 gramme as a basis for calculation in 
experiment (a) (oatmeal and milk), the yield of cholesterol attributable to 
oatmeal would have been 0°135 gramme. Milk fat, according to Schmidt and 
Mulheim, A. Bomer, and A. Kersten, contains 0°5 per cent. of crude cholesterol, 
which Menozzi has shown to be identical with that of bile. If we take our 
milk as containing between 3 and 4 per cent. of fat, the amount of cholesterol 
from this source should have been for the quantities taken in experiment (a) 
between 0°35 and 0:468 gramme. The total cholesterol to be expected 
would therefore be between 0°485 and 06 gramme. We actually found 
about 0°5 gramme. 
In experiments (e) and (g) the traces of cholesterol found could be accounted 
for as due to the food. 
Experiment (c), on a diet of sheep’s brain, is of special interest, not only 
because of the quantities obtained, but because the cholesterol was entirely in 
the form of coprosterol. The brain substance is well known to be rich in 
cholesterol. The human brain contains about 2 per cent. Whether the 
content of cholesterol in the brain of other animals is as high as this we 
do not know. On the assumption that it is the same as in the human brain 
we should have expected in the feces of a period of 14 days between 
25 and 30 grammes of cholesterol. We actually found 16 to 17 gr. of 
coprosterol. There can be no doubt that this was due to the diet. In man, 
according to Bondzynski and to Miiller(and in agreement also with our own 
experience), the change of cholesterol into coprosterol in the gut by bacteria, is 
the normal process, and if the gut is cleared of the particular bacteria by 
prolonged milk diet, cholesterol is excreted as such. 
In the dog, fed on either cooked vegetable or meat diet, cholesterol is 
normally excreted as such. In the case of raw brain we obtained coprosterol 
only. The cause of this we must reserve for future investigation. It may 
have had something to do with the fact that the food was uncooked, or that 
it was unusually rich in fat. Unfortunately, we were unable to ascertain 
