66 THE POPULAR SCIENCE MONTHLY, 



ing, perhaps, that the amount of water associated with the actual 

 starch varies, producing some small differences of density or other 

 physical variations. 



Taking arrowroot as an example. To the chemist arrowroot is 

 starch in as pure a form as can be found in nature, and he applies this 

 description to all kinds of arrowroot ; but, looking at the " price cur- 

 rent " in the " Grocer " of the current week (February 16th), I find, 

 under the first item, which is " Arrowroot," the following : " Bermuda, 

 per pound. Is. to 25." ; '• St. Vincent and Natal, 2\d. to 8Jc?." ; and 

 this is a fair example of the usual differences of price of this com- 

 modity. Nine farthings to ninety-six farthings is a wide range, and 

 should express a wide difference of quality. I have on several occa- 

 sions, at long intervals apart, obtained samples of the highest-priced 

 Bermuda, and even " missionary " arrowroot, supposed to be perfect, 

 brought home by immaculate missionaries themselves, and therefore 

 worth three and sixpence per pound, and have compared this with the 

 twopenny or threepenny "St. Vincent and Natal." I find that the 

 only difference is that, on boiling in a given quantity of water, the 

 Bermuda produces a somewhat stiffer jelly, the which additional te- 

 nacity is easily obtainable by using a little more twopenny (or I will 

 say fourpenny, to allow a good profit on retailing) to the same quan- 

 tity of water. Putting it commercially, the Natal, as retailed at four- 

 pence per pound, and the Bermuda at its usual retail price of three 

 shillings, I may safely say that nine ounces of Natal, costing twopence 

 farthing, is equal to eight ounces of Bermuda, costing eighteenpence. 

 Both are starch, and starch is neither more nor less than starch, unless 

 it be that the best Bermuda at three shillings per pound is starch ply>s 

 humbug. 



The ultimate chemical composition of starch is the same as that of 

 cellulose — carbon and the elements of water, and in the same propor- 

 tions ; but the difference of chemical and physical properties indicates 

 some difference in the arrangement of these elements. It would be 

 quite out of place here to discuss the theories of molecular constitu- 

 tion which such differences have suggested, especially as they are all 

 rather cloudy. The percentage is : Carbon, 44*4 ; oxygen, 49*4 ; and 

 hydrogen, 6*2. The difference between starch and cellulose that most 

 closely affects my present subject, that of digestibility, is considerable. 

 The ordinary food-forms of starch, such as arrowroot, tapioca, rice, etc., 

 are among the most easily digestible kinds of food, while cellulose is 

 peculiarly difiicult of digestion ; in its crude and compact forms, it is 

 quite indigestible by human digestive apparatus. 



Neither of them is capable of sustaining life alone ; they contain 

 none of the nitrogenous material required for building-up muscle, nerve, 

 and other animal tissue. They may be converted into fat, and may 

 supply fuel for maintaining animal heat, and may supply some of the 

 energies demanded for organic work. 



