35© SCIENCE PROGRESS. 



of the spermaceti eaten was collected at the fistula, but the 

 material collected melted at 36° c, and was not spermaceti 

 but ordinary tri-palmitin. Thus, the spermaceti was split, 

 and the free fatty acid finding glycerine, from what source 

 we know not, appeared as the neutral glyceride, the cetyl- 

 alcohol not beinsf detected. 



Again, the fat of the chyle is known not to be capable of 

 accounting for all the fat absorbed from the gut, so that even 

 the supporters of the corpuscular theory must admit either 

 that some soluble material is absorbed by the blood path, 

 or that the deficit is metabolised in situ. Frank ligatured 

 the thoracic duct, and still found that some portion of the 

 fatty acids with which the animal was fed was being 

 absorbed, but his blood analysis gave no help ; further, he 

 found the rapidity of output of fat at the thoracic duct on 

 feeding with fatty acids was far behind the rapidity of absorp- 

 tion from the gut, and this difference was more marked 

 than when the animal was fed with neutral fats. 



Those in favour of the corpuscular theory may 

 advance the undoubted fact that there is a distinct rela- 

 tion between the melting point of a fat and its economical 

 absorption, a fat fluid at body temperature being far 

 better utilised than one that is solid. Yet Munk and 

 Arnschinck show clearly that a certain amount of fat of 

 higher melting point than the body temperature is certainly 

 absorbed. Arnschinck, for instance, found that from 9 to 

 14 per cent, of stearin melting at 60 c, and which is fairly 

 hard even at 40° c, was absorbed. To what extent the bile 

 is necessary is not very clear. V. Wistinghausen's theory 

 of its action is hardly needed if we deny the presence of 

 capillary tubules in the " basal band " of the cylinder cells. 

 Dastre has certainly shown that if a dog is fed on a fatty 

 emulsion such as milk, it can absorb fat without bile, and 

 gain in weight ; and Munk also had a dog with biliary 

 fistula absorbing 100 grammes of lard a day, though with 

 fats of higher melting point he admits the necessity of the 

 presence of bile, for while 90 per cent, of mutton fat is 

 absorbed by a normal dog, only 36 per cent, is taken up 

 without bile. 



