Increasing Quantities of Fat in Diet on Metabolism in Dogs. 265 



the faeces, varies on different days from 86*65 to 91*03, while the fat 

 varies from 95-91 to 97*25. 



It will be well to now compare the averages of the two preceding 

 normal dogs before we discuss what occurs after the removal of the 

 large intestine. 



The normal averages are given in Table III. 



Dog 1. Table III during the three periods of the experiment (a), (b), 

 (c) received the same quantity of nitrogen, 4*82 grams. During the 

 period (a), 12*04 grams of fat were given ; during period (b), 32*04 grams, 

 and during period (c), 62*04 grams. As far as the weight was concerned,, 

 the increase of fat from 32 grams caused no real increase in the average 

 weight. The further increase to 62 grams of fat caused an increase of 

 weight from 4*59 to 4*63 kilos. 



So far as the quantity of urine is concerned, the interesting fact is 

 brought out that the increase of fat in the diet caused a progressive 

 decrease in the quantity of urine from 118 to 89 c.c., and 70 c.c. 

 respectively, and this corresponds with an increase of specific gravity 

 in the different periods. The fat also caused a decrease of the quantity 

 of nitrogen eliminated in the urine, the quantity falling from 4*457 

 to 3*575 grams, on increasing the fat from 12 to 32 grams, and still 

 further to 3*362 grams, by increasing the fat ingested to 62 grams. 

 The marked difference in the fall of nitrogen excreted during (a) and (b)> 

 when the fat was increased 20 grams, is due to the animal having been 

 on rather a small quantity of nitrogen, although on nitrogen equili- 

 brium. On the other hand, when later on the fat ingested was in- 

 creased to 62 grams, there was but a small decrease in the elimination 

 of nitrogen, because the animal was, comparatively speaking, fat. The 

 quantity of faeces steadily increased as the fat was increased in the 

 diet, rising from 18*61 to 20*42 and 22*70 grams during the periods 



<<). (). () 



The nitrogen in the faeces also steadily increased with the increase 

 of fat in the diet. Thus, on the relatively poor fat diet, 0*351 gram 

 of nitrogen was eliminated ; but, on increasing the fat in the diet in 

 spite of the fat containing no nitrogen, there was an increase in the 

 quantity of nitrogen in the fasces to 0*412 gram, which still further 

 increased to 0*469 gram when the fat in the diet was increased to 

 62*04 grams. 



The fat in the fasces also increased from 0*733 to 0*971 gram, and 

 to 1*264 grams as the fat was increased in the diet. 



That the increase of fat in the diet should cause a decrease of 

 nitrogen in the urine is what one naturally expects,* but that the 

 increase in the fat ingested should cause an increase of nitrogen in the 

 faeces is not what might have been a priori expected to occur. That 



* A. PugUese, ' Du Bois-Eeymond's Archiv,' 1897, p. 473, shows that increasing 

 the fat in a fixed diet causes a decrease in the nitrogen eliminated in the urine. 



