FOODS — HUMAN NUTRITION. 63 



examination of calf's foot jelly in comparison with jelly obtained from granu- 

 lated jelly i)Owder and pure gelatin. 



Samples of granulated jelly powders were found to contain on an average 

 from 13 to 17 per cent gelatin, about SO per cent sugar, from 1.5 to 2.5 per cent 

 tartaric or citric acid, and certain flavoring and coloi-ing matters. 



To insure transparency in such jellies the water added should be below 90° 

 O. in temperature. The jellies may be strained through muslin if necessary. 



Various questions concerned with jelly and jelly making are discussed, par- 

 ticularly meat jellies. 



Quotations from the author's discussion follow : 



"A table jelly [made with gelatin, such as is often used for dessert] consists 

 of water, gelatin, sugar, fruit essence, and a vegetable acid. As the essential 

 part of a jelly other than sugar is gelatin it will only be necessary to consider 

 this from a chemical and physiological point of view. . . . 



" By continuous boiling with water gelatin is converted into a nongelatinizing 

 form called /3-gluten, and this reaction may partly account for the fact that 

 some jellies will not set under any ordinary conditions. In the same way 

 repeated heating and cooling destroys the property of gelatinizing, and the 

 power to form a jelly is entirely lost by heating under increased pressure to 

 140° C. 



"Aqueous solutions of the salts of monobasic acids, except alkali formates and 

 acetates, retard the coagulation of gelatin, while salts of the dibasic and tribasic 

 acids, polyhydric alcohols, and sugars increase the rate of coagulation. Crys- 

 talloids which increase the viscosity of water increase the viscosity of col- 

 loidal solutions. . . . 



" Gelatin has one great advantage — that it is easily digested in the stomach, 

 and also has the power of fixing excess of acidity ; thus it can well be pre- 

 scribed in certain disorders of the gastric digestion. In the first stage of 

 digestion it loses its property of gelatinizing, and is formed into gelatin pro- 

 teoses, gelatose, and gelatin peptones. . . . 



" What little nutritive value table jellies contain is dependent more upon the 

 sugar, amounting to from 50 to SO per cent, than upon the smnll amount of 

 gelatin present. The gelatin usually amounts in most table jellies to from 13 

 to 17 per cent, hence as protein sparers in certain ailments their usefulness is 

 somewhat restricted, and there Is no reason to suppose that gelatin is converted 

 into protein within the body. As a source of heat and energy it has decided 

 value, for 1 gm. yields nearly as much of these as 1 gm. of protein or carbo- 

 hydrate — namely, 4.1 calories. Ordinary gelatin produces 1,570 calories per 

 pound." 



The author describes the method which he follows in the examination of 

 materials containing gelatin. 



Lacto — a new and healthful frozen dairy product, M. Mobtensen and 

 J. Gordon (loica Sta. Bui. 118, pp. 268-279, charts 2).— The authors have 

 obtained favorable results in a study of the preparation of a frozen product 

 of the same consistency as ice cream, made from fermented milk, to which eggs, 

 sugar, and flavoring material have been added. 



It is stated that even when buttermilk of good quality has been used it has 

 not been possible to produce a combination of flavors which was entirely 

 palatable. On the other hand, when milk soured with a commercial lactic-acid 

 culture was used the product, for which the name " lacto " is proposed, was 

 found to be satisfactory. 



Directions are given for souring the milk which, when ready for use, has an 

 acid content of from 0.7 to 0.8 per cent expressed in terms of lactic acid. The 

 milk must be " of a mild and clean acid flavor. The curd must be thoroughly 



