260 Prof. V. Harley. Influence of Removal of Large Intestine and 



Rieder* found that on feeding dogs with a nitrogen-free diet the 

 faeces contained absolutely more nitrogen than during fasting, and 

 often than that obtained on a pure meat diet. A dog on 500 grams of 

 starch-meal gave 0'7 gram, with 700 grams of starch-meal it gave 

 0'8 gram of nitrogen in the fseces; while with 1500 grams of meat the 

 faeces only contained 0'67 gram of nitrogen. 



J. Tsuboif has lately carried out the same researches with the 

 greater accuracy of modern methods in Professor Yoit's laboratory, 

 and his results show that the nitrogen of the fseces on an absolutely 

 nitrogen-free diet is greater than that during fasting, and the quantity 

 of nitrogen increases with the quantity of food. In fact, the quantity 

 of nitrogen in the fseces on a nitrogen-free diet may be as much as 

 that found on the diet of meat rich in nitrogen. 



It is thus seen that on such a diet the greater quantity of the nitro- 

 gen of the fseces must be regarded not as a nitrogen residue, but as 

 the product of metabolism. 



It has already been stated that the contents of the Hermann's loop 

 are probably to be regarded as consisting of such metabolic products ; 

 and, as I have already shown in this paper, the large intestine behaves 

 in exactly similar manner. Although by calculations on animals and 

 man, one has a rough idea of the daily quantity of nitrogen and fat 

 that ought to be eliminated during fasting, and although one can 

 subtract that amount from the quantity found in the fseces, in the case 

 where the large intestine was removed this could not be done, as we 

 have no data showing the daily quantity of nitrogen or fat that is 

 eliminated by the large intestine. It was therefore considered better 

 in calculating absorption of proteids and fat, to neglect from the esti- 

 mation the quantities probably excreted in fasting. 



We will now consider the experimental details, and in the first 

 instance I will refer to two normal dogs, which are taken for the pur- 

 pose of comparison with those in which the large intestine was removed, 

 and in which the quantity of fat ingested during various periods was 

 steadily increased. These details are given in the following table 

 (p. 261). 



Dog 1. In the preceding Table I we see the influence of the addi- 

 tion of fat to the diet on the absorption and metabolism in a normal 

 dog. 



In this table the sterilised meat was commenced eight days previous 

 to the first analysis, the animal being on nitrogen equilibrium. The 

 diet consisted of sterilised beef, biscuit, and small quantities of fat ; 

 water was given twice a day, and the dog was allowed to drink as 

 much as she pleased each time. 



(a) During the first period of four days the quantity of nitrogen in 



* Eieder, ibid., vol. 20, p. 382, 1884. 

 f J. Tsuboi, ibid., vol. 35, p. 76, 1897. 



