74 MASS. EXPERIMENT STATION BULLETIN 388 



as a source of nitrogen. The biological value of crab protein was approximately 

 the same as that of good grade fish meal. Pigmentation in chicks was slightly 

 increased by feeding crab meal as compared with fish meal. In the New England 

 Conference Chick Starter ration the replacement of fish meal by crab meal on 

 either an equal-weight or equal-protein basis gave results highly complimentary 

 to crab meal. Crab meal sells at considerably lower prices than fish meal; it 

 would seem to be a very satisfactory ingredient of poultry rations. 



Dextrose Investigations. (C. R. Fellers, A. S. Levine, and L. Tarkow.) Studies 

 have been concluded on the relative bacteriostatic and mycostatic properties of 

 sucrose, dextrose, and mixtures of the two sugars. Dextrose kills and prevents the 

 growth of bacteria, yeasts, and molds at lower concentrations than does sucrose. 

 That is, dextrose sirups (above 30 per cent) are far less liable to ferment or mold 

 than similar sucrose sirups. The use of dextrose in canned foods, in carbonated 

 beverages, and in soda-fountain crushed fruits and sirups is rapidly increasing. 

 The smaller molecule and the greater osmotic pressure exerted by dextrose in 

 solution are believed to contribute to the greater preserving value of this sugar. 



Red Squill Research. (A. S. Levine, C. R. Fellers, and J. Lubitz.) Improved 

 methods for rat extermination are now more important than ever before in re- 

 ducing the nation's loss by waste. 



Red squill was found to be harmless for chickens and rabbits. Guinea pigs 

 are more susceptible than rats to red squill poison. Some popular flavors have been 

 found to be of little value as rat lures. Among these are meat, cheese, anise, 

 caraway, cinnamon, and peppermint flavors. The composition of common baits 

 used as carriers for the squill had little effect on the toxicity of the poison to 

 albino rats. 



On account of the war there is now no importation of red squill, and most 

 stocks of red squill still in this country are of low toxicity to rats. Through con- 

 centration and subsequent bioassay studies an attempt is being made to increase 

 the toxicity of the present supply. 



Three papers have been published on red squill research. 



Preservative Values of Organic Acids. (A. S. Levine, R. E. Morse, and M. G. 

 O'Connor.) The addition of small amounts of acetic acid (vinegar) does much 

 to improve the keeping qualities of soda fountain sirups and fruit juices with no 

 impairment of flavors. The addition of only 0.3 percent acetic acid inhibited 

 both yeast and mold growth in strawberry and raspberry sirups. This is es- 

 pecially favorable when compared with the high amounts of citric and lactic 

 acids required for complete inhibition. More than 6 percent citric acid or 5 per- 

 cent lactic acid was necessary to inhibit yeast growth in these sirups. Four per- 

 cent lactic acid prevented mold growth but the mold, Aspergillus tiiger, grew in 

 sirups containing over 7 percent citric acid. 



Benzoic acid and especially sodium benzoate are still used extensively for the 

 suppression of yeasts in the preservation of fruit juices and sirups. A study is 

 now in progress to determine the effect upon yeasts when definite concentrations 

 of sucrose, dextrose, alcohol, and sodium chloride are used in conjunction with the 

 benzoates. In the preservation of apple juice as much benzoate was required to 

 preserve the clarified as was needed for the unclarified or cloudy juice. 



