Increasing Quantities of Fat in Diet on Metabolism in Dogs. 301 



in the amount of aromatic sulphates. The total quantity of aromatic 

 sulphates in this dog is very much decreased, being only from 0*026 to- 

 0-035 gram as against 0*064 to 0'082 gram in the normal dogs. We 

 therefore see that the absence of the large intestine in this case caused 

 a very marked decrease in the amount of aromatic sulphates, and this 

 decrease in the amount of aromatic sulphates was, doubtless, due to- 

 the decrease of intestinal putrefaction, and explains how it was that 

 urobilin was found in such small quantities in the faeces. 



As far as the ratio of alkaline to aromatic sulphates is concerned, in 

 the two periods with the small quantity of fat the ratio is 17:1 and 

 22 : 1, while during the two periods with the large quantity of fat the 

 ratio was 13 : 1 to 12:1. 



We have here even more markedly than in the normal dog the error 

 brought out by only noting the ratio, and not the absolute quantity, of 

 aromatic sulphates, for with a ratio of 12 : 1, as compared to that of 

 22 : 1, we should think the aromatic sulphates were very markedly 

 increased if we did not know that this alteration in the ratio was due,, 

 not to an increase of the aromatic sulphates and therefore increase in 

 the intestinal putrefaction, but simply to the decrease of alkaline- 

 sulphates in consequence of the proteid-sparing action of the increased 

 fat in the diet. 



In Table XXV, dog 5, only two periods were investigated. Here 

 we see that a very marked diminution in the quantity of nitrogen was 

 produced by increasing the fat from 11 '55 to 41 '55 grams. Accom- 

 panying this is an equal diminution in the quantity of alkaline sulph- 

 ates. The aromatic sulphates in this case also were decreased in 

 amount by increasing the fat ; in consequence of this, the ratio in this 

 dog remains much the same. 



In Table XXVI are placed together the averages obtained in the 

 preceding dogs, and it is seen that they compare very well with one 

 another. 



As a general conclusion, one may say that in all cases the increase of 

 fat causes a decrease in the quantity of sulphates, and at the same time 

 tends to decrease the quantity of aromatic sulphates; that in the 

 absence of the large intestine this still holds good, although the aro- 

 matic sulphates are extremely small in amount. 



It is thus useless to consider the ratio of alkaline to aromatic sulph- 

 ates as an indication of the amount of intestinal putrefaction, unless the 

 diet is poor in fat. 



It is also important to note that the amount of proteid itself given 

 in the diet does not influence the amount of aromatic sulphates nearly 

 as much as one would expect, for in dogs 1, 2, and 3, in spite of the 

 proteid varying in quantity very considerably, the quantity of aro- 

 matic sulphates remained the same. 



