664 EXPERIMENT STATION RECOED. [Vol.36 



when the food contained adequate protein with the same proportion of fat. 

 By underfeeding gain in weight was arrested and constant weight maintained 

 for 30 and 60 days. Comparison of the composition of these stunted mice with 

 that of mice growing normally showed that " the proportion of fat in the 

 stunted animal is about the same as in the normal mouse of the same weight 

 (but younger), while the percentage of water in the fat-free substance cor- 

 responds to the water content of a normal mouse of the same age (but 

 heavier)." The ash content of the stunted mice was greater than that of the 

 normal mice of the same weight. 



Retardation of growth by reduction of protein or salts in the food or by 

 substitution of gliadin for other proteins affected the ash content of the animal 

 in the same way as did underfeeding. Young mice maintained for a tiu;e 

 at constant weight when given sufficient food again grew at a greatly ac- 

 celerated rate, which enabled them to overtake control mice which had growTi 

 uninterruptedly. The ash content, however, did not increase at the same rate 

 and the development of the skeleton did not, in the active growth which ac- 

 companied refeeding, keep pace with the rapid gain in body weight, so that 

 in a few days the normal relation was almost reestablished. 



Ammonia and amino acids in the stomach and intestinal content with 

 exclusively vegetable diet, G. Agnoletti {Arch. Farmacol. Sper. e Sci. Aff., 

 22 (,1916), No. 7, pp. 261-273). — From observations on animals (horses and 

 asses) the following conclusions were drawn: 



A part of the nitrogenous portion of the soluble fraction of the stomach con- 

 tent not found as total nitrogen was present in the form of ammonia, and a 

 much greater part in the form of amino acids. The quantities of ammonia 

 nitrogen and nitrogen titratable as formol found in the intestine exceeded the 

 quantities found in the stomach. In general with each group of animals re- 

 ceiving the same food (hay, Indian corn, and oats) a high percentage of amino 

 acids in the intestinal content corresponded to a high percentage of amino acids 

 in the soluble portion of the stomach content. 



The influence of milk and carbohydrate feeding on the character of the 

 intestinal flora. — IV, Diet versus bacterial implantation, T. G. Hull and 

 L. Rettgeb {Jour. Bact., 2 {1917), No. 1, pp. Jfl-71). — The experiments here re- 

 ported were made vrith laboratory animals (white rats) and are a continuation 

 of earlier experiments (E. S. R., 33, p. 460). These were supplemented also 

 by experiments with other laboratory animals and men. The following con- 

 clusions are drawn in part from the data presented : 



Bacillus acidophilus (Moro) and B. bifldus (Tissier) are common inhabitants 

 of the intestinal tract of the white rat and of man, soaietimes being present in 

 small numbers and at other times excluding all other forms, at least for short 

 periods. " The typical flora of infants which subsist on mothers' milk is a 

 good illustration of the extent to which one intestinal organism {B. bifldus) may 

 dominate and even supplant all other types. The most important factor in 

 determining the character of the flora is the diet. 



" Lactose, milk, and mixed grains (wheat, oats, etc.) are specific articles of 

 diet which exert an influence on the intestinal bacteria. Lactose, when fed in 

 sufficient quantities (2 or 3 gm. daily), brings about a complete transformation 

 of the flora of white rats within two or three days ; milk requires a longer time, 

 and does not bring about a complete change. Milk and lactose together form the 

 most practical and effective diet, at least for man. Grain feeds tend to increase 

 the number of aciduric bacteria, but their influence is comparatively small. 



" Milk undoubtedly owes its beneficial action to the lactose, which constitutes 

 almost half of the solid matter present. The explanation of this action must 

 lie in the fact that the lactose is absorbed slowly from the intestine. On several 



