1908.] Destiny of Cholesterol in the Animal Organism. 119 



Experiment VIII. — In this experiment the sheep's brain was lightly fried 

 in its own oil before being given, in order to ascertain whether the cooking 

 process had any influence on the conversion of the cholesterol to coprosterol. 

 The cat selected weighed 2 - 9 kilogrammes, and during the feeding period of 

 14 days lost 0"4 kilogramme in weight ; 1913 grammes of brain (weighed 

 uncooked) were consumed, and 365 grammes of dried faeces obtained. These 

 were of very much the same constituency as before, and were treated in a 

 similar manner ; 23 grammes of unsaponifiable matter in the form of a red 

 oil were obtained. This proved very difficult to purify, owing to the tarry, 

 sticky oils present, and we were only able to isolate 7'4 grammes of white 

 crystalline matter, which proved to be a mixture of cholesterol and coprosterol. 

 The cholesterol taken (on the above assumption) shoidd therefore be 

 38 grammes, the total unsaponifiable matter being only 23 grammes. The 

 cooking and consequent partial sterilisation of the brain seem, therefore, to 

 have interfered with the conversion of the cholesterol into coprosteroL 



Experiments to ascertain whether any of the Cholesterol which 

 disappears from the food can be found in the blood. 



Herbivorous Animals. 

 Pribram* has stated that on administering cholesterol to rabbits per os, an 

 increased percentage of this substance could be found in the blood. His 

 method consisted in injecting into the stomach of the animal an emulsion 

 of cholesterol, cholesterol oleate, or cholesterol palmitate, made up with 

 olive oil. After some hours the animal was killed, and the cholesterol in the 

 blood determined in the usual way. But from the point of view of proving 

 that cholesterol taken by the mouth can be absorbed into the blood stream 

 these experiments seem to us for several reasons by no means conclusive. 

 In the first place, the rabbits studied were far from being under normal con- 

 ditions of diet. A comparatively large dose of oil was put into the stomachs 

 of animals who are not accustomed to take or assimilate fats in this form. 

 Pribram mentions that the oil passed into the blood as the serum became 

 opalescent, and it seems to us not improbable that, with a quantity of oil in 

 the stomach which cannot be assimilated in the ordinary way, some of the 

 oil might percolate, if one may use the term, into the blood, carrying the 

 cholesterol with it. The supposed increase, therefore, found in the blood 

 might not unreasonably be due to a mechanical rather than to a metabolic 

 process. But a further consideration of the data given by Pribram led us to 

 doubt whether they could be considered as showing that there was an increased 

 percentage of cholesterol. 



* ' Bioch. Zeit.,' vol. 1, p. 414. 



