236 Messrs. Dorée and Gardner. Origin and  [Feb. 10, 
If we take the mean of the above results as approximately correct, the 
daily secretion of bile by our dog would be 291 grammes. 
For the content of cholesterol in 100 parts by weight of dog’s bile, Hanne: 
Seyler gives the following figures :— 
(a) Bile from bladder. (6) Bile from fistula. 
(Ca A, Cae eS) 
i II. 1; i 
0-449 0133 0-074 0-049 
We do not know how far the bile poured into the gut would resemble 
either bladder bile or fistula bile, but, calculating on the basis of the lowest 
and highest values given, our dog should have received into its intestine, 
along with the bile, between 0°14 and 1°31 grammes of cholesterol per day. 
If it be the case that cholesterol is a true excretion product got rid of in the 
feeces through the agency of the bile, this quantity should have been found 
in the excreta along with that contained in the food consumed, whereas, as 
shown in the following table, in which we compare the amounts of cholesterol 
actually found in our experiments with those that should have been found 
on the assumption that the cholesterol of the bile is all excreted in the feces, 
the amounts found in most cases were less than one-fifth of the lowest of the 
above -values. 
It is clear from the above experiments that the whole of the cholesterol 
of the bile is not excreted in the feces. It must, therefore, have been 
either totally destroyed, which, considering the great stability of cholesterol, 
is highly unlikely, or reabsorbed in the gut along with the bile salts, 
which is the more reasonable explanation. It might be contended that 
the cholesterol had been changed in the intestine into the unsaponifiable oil 
found along with the cholesterol, but this is probably not the case, as the oils 
obtained were very variable, both in quantity and appearance, and further, 
the weights of such oils obtained were usually quite insufficient to account 
for the cholesterol. 
How far the quantities of cholesterol found can be accounted for as 
cholesterol contained in the food and passed unchanged is more difficult to 
answer, as we have little exact knowledge of the cholesterin content of the 
various food stuffs. In our opinion, however, it can be largely accounted for 
in this way. 
Considering the two een with cooked meat, in which the 
cholesterol recovered for 20 days was only 0°6 and 1:0 respectively, these 
amounts might well have been due to the food taken. As is well known, 
animal flesh contains cholesterol, though quantitative estimations have, as far 
as we are aware, not been made. Such estimations would be tedious and 
