ITS QUANTITY. 293 



themselves of the correctness and general applicability of Bous- 

 singault's observation; for they found that cats weighing 1000 

 grammes were able to take up from 0'6 to 0'9 of a gramme of fat 

 in one hour, the surplus being carried off with the excrements. It 

 is far more probable that all the resorbed fat should reach the blood 

 through the lacteals, than that all the protein-bodies should pass 

 into the chyle ; and hence we shall probably obtain a nearer ap- 

 proximate number for the chyle which passes hourly into the blood, 

 by adopting the amount of fat in the chyle of cats as the other 

 basis of our calculation. Nasse, as has been already observed, 

 found 3'27 of fat in the chyle of a cat; now, if no lymph flowed 

 into the chyle, and if we assume that lymph contains some, although 

 not much, fat (for Tiedemann and Gmelin found only traces of fat 

 in the contents of the thoracic duct of fasting horses), and if it were 

 shown that the chyle does not actually lose any fat in the mesenteric 

 glands (this substance only becoming saponified), and that all the 

 fat of the chyle of the thoracic duct has originated directly 

 from the intestinal contents, cats weighing 1000 grammes 

 would pour 22-9 grammes of chyle into the blood in one hour 

 (supposing that they absorbed 0'75 of a gramme of fat in the same 

 time), or 549'6 grammes of chyle in 24 hours. But as this would 

 be more than half their weight, it is very improbable that this is the 

 correct quantity. If we assumed six hours as the period during which 

 true chyle passes into the blood, a cat weighing 1 kilogramme would 

 daily elaborate 13 7 '4 grammes of chyle. These calculations, more 

 especially when they are extended to the human organism, are, 

 however, far too uncertain to afford any stable support to our 

 future inquiries into the mechanical metamorphosis of matter, for 

 there exist innumerable relations by which the result of such cal- 

 culations may be completely modified. It would carry us too far 

 from our subject were we to enumerate all these relations ; we will, 

 therefore, simply remark that probably a large quantity of fat is 

 not conveyed from the chyme to the lacteals, but is resorbed by 

 the veins, for how otherwise could the portal blood of animals be 

 almost twice as rich in fat during the process of digestion as in the 

 fasting condition ? (See p. 247.) 



We cannot entertain any doubt as to the origin of the chyle, 

 since nature itself has clearly manifested its source to us. Certain 

 questions here present themselves as to the mode in which the 

 individual constituents pass into the lacteals, and the alterations 

 which they undergo within these vessels. The lacteals originate 

 in the axis of the villi which are spread over the whole of the small 



