July 15, 1932
INDUSTRIAL AND ENGINEERING CHEMISTRY
parts per million may be proportionately decreased. However, the use of a larger original sample for the PZOs plus SiOz is not feasible, since in most cases it would make the quantity of SiOz greater than that which may be measured accurately by this technic. If only the total PzOj is to be determined, this limitation does not hold, and in general weights of sample up to 15 grams may be used.
TABLE111. Si02 AND PtOb SAMPLIJ
Si02 P. v. 7n.
IN
WHITESUQARB
ORQANIC P ~ O S INORQANIC PZOS P. p . m. P. v. m. 0.0
0.8
1.1 1.1
0.5
0.6 0.6 0.3 1.1 1.1
6.0 0.3
Trace Trace 0.1
Trace Trace 0.3 Trace 0.0
The values for organic PZOS recorded in the previous article (1) are incorrect in that they include a part of the Si02 as well as the actual organic phosphorus. Unfortunately the samples of the sugars on which those analyses were made have been exhausted, and therefore the correct values cannot be given. Table I11 gives the values found in more recent sugar samples representing both refined and direct-consumption cane sugars, as well as beet sugars. It is to be noted that the quantity of Si02 greatly exceeds that of the organic phosphates. The results indicate that thk silica in the sugars is in a nonreactive form, since it does not give the reaction until after it has been made soluble by carbonate fusion, as shown in those cases which contain silica but which give no test for inorganic phosphates. The extreme ease with which
327
the silicate ions pass into nonreactive complexes is shown by the impossibility of preserving the standard silicate solutions and by the following experiment which was performed in triplicbte: A solution of water glass containing 0.109 mg. of reactive silica was added to 10 grams of sugar “A” and heated in a vacuum oven a t 70” C. for 24 hours. After the lumps had been broken up, the sugar was allowed to stand in the open air for 7 days. A determination by the procedure for inorganic phosphates showed no more color than that developed in the blank on the reagents. Since by this simple treatment the silica was rendered nonreactive, there is no reason to suppose that silica in the juices will remain in the active form throughout the more vigorous treatments used in the processes of manufacturing white sugar. ACKNOWLEDGMENT The tests for arsenic were made by C. R. Gross of the Insecticide Division, Bureau of Chemistry and Soils, Department of Agriculture, to whom the authors extend their thanks and appreciation. LITERATURE CITED Byall and Ambler, IND.ENQ.CHIM.,Anal. Ed., 3, 136 (1931). Foulger, J. Am. Chem. SOC.,49, 429 (1927). Isaacs, BUZZ. SOC. chim. biol., 6, 157 (1924). Oberhauser and Schormuller, 2. anorg. Chem., 178, 381 (1929). Pincussen, Roman, Minr, Politzer, and Rothmann, Biochem. Z., 233,344 (1931). (6) Woodman and Cayvan, J. Am. Chem. SOC., 23, 96 (1901).
(1) (2) (3) (4) (5)
RECEIVEDFebruary 25, 1932. Presented before the Division of Sugar Chemistry a t tbe 83rd Meeting of the American Chemical Society, New Orleans, La., March 28 to April 1, 1932. Contribution 122, Carbohydrate Division, Bureau of Chemistry and Soils.
A Convenient Feed Cup for Rats R. W. PILCHER, American Can Company, Maywood, 111.
T
HE feed cup described by McCollum ( I ) is a useful device
filled with feed and the smaller forced down into position, for feed conservation in nutrition studies. Frequently, the rat must reach through the hole in order to consume however, the materials available locally for its construction the ration. The cup appearing in the photograph was con~ in diameter. The are of such proportions that the cup occupies considerable structed from cans of 211/16and 2 * / inches space within the cage and requires an excessive amount of hole in the end of the inner can is 1inch in diameter. The cup may be suspended from the top of the cage by feed to fill it. Large amounts of feed are consequently lost wires or permanently attached to the side. In the latter during periodic renewal of the ration. A feed cup constructed entirely from tin cans has been case it will be found that, by fastening the cup to the cage a t a devised for use in this laboratory. Its construction is quite decided angle, the possibility of excreta lodging in the cup simple, as the accompanying photograph indicates. Two as a result of the animal perching upon it will be greatly cans of closely similar diameters are chosen so that one will reduced. The device is c o m p a c t readily fit within the other and easily manipulated and without binding. The cans cleaned. M a n y standard a r e c u t t o approximately can sizes are available, makthe same height on a lathe ? ing possible the construction or by means of tin shears. /! of a n u m b e r of different A round hole is then made sized feed containers. in the end of the inner can by a lathe or round tinner’s punch. The hole s h o u l d LITERATURE CITED be of sufficient size to per(1) M c C o l l u m , E. V., and m i t e a s y entrance of the S i m o n d s , x., “ T h e animal’s head. Diameters N e w e r Knowledge of of 1, 1.125, and 1.25inches Nutrition,” 4th ed., p. have been found to be the 79, Macmillan, 1929. . most useful sizes. COMPONENT PARTSSHOWING METHODOF ASSEMBLY AND When the larger can is SUSPENSION RECEIVED February 16, 1932.
