ADDITIONS AND NOTES TO VOL. II. 509 



to amylaceous food ; but the case was very different when the 

 quantities of fat were compared with one another which were 

 retained in the body and applied to the purposes of life by the 

 animals that had been operated on and by the healthy animals. 

 It was ascertained by Boussingault (see vol. i, p. 255), and the 

 fact has been confirmed by Bidder and Schmidt, that the animal 

 organism is only able to absorb a definite, and indeed a somewhat 

 small quantity of fat from the intestinal canal. Several experi- 

 ments on cats have shown that the full-grown animal is at most 

 able to take up 0'6 of a gramme of fatty food for every kilo- 

 gramme of its weight during the 24 hours, while young animals 

 absorb as much as 0*9 of a gramme. Similar experiments with a 

 dog (which weighed 5 kilogrammes) showed that this animal had 

 resorbed 446*9 grammes of fat in a week ; consequently, every 

 kilogramme's weight of the animal would be able to digest at 

 least 0*465 of a gramme of fat in one hour, when plentifully sup- 

 plied with that substance. These animals, however, absorbed 

 much less fat when the passage of bile was entirely excluded from 

 the intestine ; in three series of experiments on these animals it 

 was found that in one case, where the access of bile was prevented, 

 for every kilogramme of the animal's weight only 0*093 of a 

 gramme of fat was absorbed, in another case 0*065 of a gramme, 

 and in the third case 0*21 of a gramme. It is very clearly seen 

 from these experiments, that a certain quantity of fat will be 

 absorbed independently of the presence of the bile, although this 

 is 2J times less in the most favourable cases than the amount of 

 fat which is absorbed in conjunction with the secretion of bile. 

 The opposite experiment of Blondlot,* in which he could scarcely 

 detect a trace of fat in the excrements of a dog having a biliary 

 fistula, and which had been fed on very fat food, has been, for 

 various reasons, and perhaps correctly, referred by Bidder and 

 Schmidt to the fact that a free passage through the Ductus 

 choledochus may probably have been re-established in the animal. 

 The participation of the bile in the digestion of fat must, therefore, 

 be considered as settled beyond a doubt, although it cannot be 

 wholly denied that a small portion of the fat may be resorbed 

 independently of the co-operation of the bile. 



As it is well known that the white colour of the chyle is mainly 



owing to the amount of fat which it contains, the colour of the 



chyle contained in the lacteals was observed after the bile had been 



excluded from the intestine ; but this experiment -was attended by 



* Essai sur les fonctions du foie et de ses annexes. Paris, 1846, p. 52. 



