682 



oxidized (burned) in the body, aud this leads the author to suggest 

 tliat they may possess certain fuel values, by tlieir combustion pre- 

 venting other materials from consumption. 



It is known that starch and all digestible carbohydrates possess a 

 high value as food, and that so far as they are not changed into fat 

 within the organism and as such stored in the body, they are burned 

 to carbonic acid and yvater, thus decreasing the destruction of the 

 albuminoids and diminishing the loss of fat from the body. 



To determine whether the acetic and lactic acids occurring in certain 

 foods exert an action similar to that of carbohydrates in conserving 

 the albuminoids the following experiments were made : A rabbit was 

 placed in a small zinc stall, with arrangements for collecting the solid 

 aud liquid excreta. The food consisted in the first period of 15 grams 

 ground meat (containing 1.94 grams nitrogen and 1.8 grams fat), 30 

 grams starch, 10 grams sugar,- 5 grams nutshells, 0.5 gram ash of 

 hay, and 0.2 gram salt per day, with water ad libitum. The nutritive 

 ratio of this ration was 1 : 3.7. The ingredients were mixed with hot 

 water to a homogeneous plastic mass, kneaded, dried, and the mass 

 broken into pieces the size of a pea, for feeding. By this means it was 

 possible to feed the whole ration without waste. 



For 10 days, following a preparatory period of 8 days, the urine was 

 carefully collected and the nitrogen in the same determined. The live 

 weight remained quite constant at 2,390 grams. The average excre- 

 tion of nitrogen in the urine was 1.4G grams per day. In the second 

 period, immediately following the first, 10 grams of starch were replaced 

 by 10 grams of acetic acid in form of calcium acetate for 1 day and of 

 sodium acetate for 2 days ; but this food being refused by the animal, 

 IS grams of calcium lactate (=10 grams lactic acid) were substituted 

 for 4 days. At the end of this time it was apparent that the acid could 

 not be successfully fed for any length of time, and the food was 

 changed. The live weight had fallen to 2,132 grams. The nitrogen 

 in the urine averaged per day for the first 3 days 1.96 grams, and for 

 the last 3, 1.87 grams, or 1.92 grams for the period. The excretion of 

 nitrogen had, then, increased about 30 per cent over that of the first 

 period, although the food was not all eaten and therefore considerably 

 less nitrogen was consumed. The urine had a strong alkaline reaction 

 and was rich in carbonates. Neither acetic nor lactic acid could be 

 detected at any time, and it is believed they were completely burned 

 to carbonic acid. The author concludes that the addition to the food 

 of 4.3 grams of acetic or lactic acid per 1 ,000 grams live weight did 

 not conserve the albuminoids of the body, but on the contrary probably 

 increased the albuminoid metabolism. 



The food in the third period was the same as in the second, and in 

 the fourth only differed by a reduction of the starch fiom 30 to 20 

 grams per day. The feeding of the latter ration was accompanied by 

 a falling ott'of 65 grams in live weight in 4 days, and an increase of the 

 excretioa of nitrogen iu the urine to 1,71 grams j)er da^y (period Ij 1,46 



