Increasing Quantities of Fat in Diet on Metabolism in Dogs. 26T 



this Is due to an increased excretion or secretion from the intestines 

 seems unquestionable, as already suggested by Yoit, Miiller, &c. 



When we turn to the question of absorption, we find that so far as 

 the nitrogen is concerned an increase of fat causes a decrease in the 

 percentage of absorption, while, as in period (a), with 12*04 grams of 

 fat, 9271 per cent, of the nitrogen was absorbed; on increasing the 

 fat to 32-04 grams, 91*45 per cent, was absorbed; and on still further 

 increasing it to 62*04 grams, 90*26 per cent, was absorbed. 



The fat absorption, on the other hand, instead of decreasing with 

 the increase of fat in the faeces, really increased, so that it would 

 appear as if there was a greater absorption of fat on a diet rich in fat 

 than on one poor in fat. 



In period (a) only 93*91 per cent, of the total fat given was ab- 

 sorbed, as compared with 96-97 in (b) and 97-96 per cent, in (c). This 

 apparent increased percentage of absorption of fat must be attributed 

 to the quantity of fatty matter excreted normally from the intestine, 

 so that when the fat in the diet is small this quantity alone is sufficient 

 to alter the apparent percentage very markedly. On the other hand, 

 when the quantity of fat in the diet is large the small quantity ex- 

 creted by the intestines makes little difference in the quantity in the 

 faeces, so that the percentage absorbed appears to be higher than what 

 is really the case. 



Continuing the discussion of the normal averages, we now come to 

 dog 2 (vide Table III). 



In the first two periods (a) and (b) the diet was exactly the same, the 

 reason being that the individual days fluctuated so much that it was 

 thought better to do two periods for a normal standard. 



It is seen the quantity of urine was 119 and 108 c.c. per diem 

 during the two periods (a) and (b). The same may be said of the 

 nitrogen in the urine, which was 6'127 and 5*815 grams ; the parallelism 

 of the two periods is therefore close. 



The faeces amounted to 31-67 and 33'62 grams, and the quantity 

 of nitrogen in the fasces during these two periods was 0*696 and 

 0*799 gram, while the fat was 0'776 and 0*898 gram respectively. 



The percentage of absorption of the proteids was 91*29 and 90*01 

 per cent., while the absorption of fat was 94*68 and 94*09 per cent. 



On increasing the fat to 65*19 grams the animal increased in weight. 

 The quantity of urine fell to only 74 c.c., while the specific gravity 

 rose to 1061. The total quantity of nitrogen in the urine fell very 

 markedly to 3*858 grams ; the quantity of faeces rose to 36'26 grams, 

 and contained 0*901 gram of nitrogen, so that the quantity of faeces 

 and nitrogen had increased on increasing the fat in the diet in the 

 same manner as in the case' of the preceding dog. 



The fat in the faeces increased to no less than 2*249 grams. In this 

 case 88*73 per cent, of the nitrogen and 96*55 per cent, of the fat was 



