WATER HOLDING CAPACITY OF CALLUS :267 TAULE 1--MoisTURE SOKPTION Or UNWASHED CALLUS• $ GLYCEROL AND THEIR MIXTURES Time Moisture Required Storage Conditions Absorbed at to Reach -----Composition, gm.----, Temp., R.H., Equilibrium, Equilibrium, Callus Glycerol øC. % % days 0.2175 ... 23 45 0.1851 23 45 ... 0.'1¾72 23 45 0.1539 23 45 0.'13'57 0.2852 23 45 0.1097 0.3077 23 45 0.1055 ... 37 40 0.1228 37 40 ... 0.'1¾18 37 40 0.1787 37 40 0.'68'25 0.3193 37 40 0.1084 0.3134 37 40 0.1690 ... 23 60 0.1738 23 6O ... 0.'1'8'54 23 60 0.2465 23 60 0.'6•97 0.2335 23 60 0.0988 0.1924 23 60 0.1233 ... 23 90 0.1353 23 90 ... 0.'1¾89 23 90 0.1749 23 90 0.'1'1•0 0.2486 23 90 0.1513 0.3397 23 90 6.9 6.7 19.1 19.2 13.5 14.6 4.1 3.6 17.2 17.3 14.1 13.2 11.2 11 7 38 3 38 2 29 6 28 2 34 0 34.0 176.0 178.0 129.0 129.0 4 4 6 6 5 6 1 1 4 4 21 21 6 6 6 6 6 6 12 12 36 36 36 36 * Lot #2, frozen, pounded. TABLE 2--MOISTURE SORPTION' OF UNWASHED CALLUS• • PROPYLENE GLYCOL AND THEIR MIXTURES ,.- Composition, gm. , ,--Storage Conditions--, Propylene Temp., R.H., Callus Glycol øC. Time Moisture Required Absorbed at to Reach Equilibrium, Equilibrium, % days 0.1851 ... 23 45 6.7 4 0.2175 23 45 6.9 4 ... 0.•1'84 23 45 19.2 3 0.2071 23 45 18.7 3 0.'1¾45 0.2952 23 45 15.0 3 0.1417 0.2945 23 45 14.3 3 0.1690 ... 23 60 11.2 6 0.1738 23 60 11.7 6 ... 0.¾519 23 60 32.0 7 0.1858 23 60 31.7 7 0.'1'426 0.2149 23 60 24.4 3 0.0952 0.1944 23 60 25.4 3 * Lot #2, frozen, pounded. of mixtures of callus with glycerol, with propylene glycol and with crys- talline sorbitol is made in Table 4. The method outlined by Flesch (22) was used to obtain the calculated values shown in Table 4. It is indisput- able that neither glycerol, propylene glycol nor crystalline sorbitol po-

268 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS TABLE 3--MoisTURE 5ORPTION OF UNWASHED CALLUS•* CRYSTALLINE SORBITOL AND THEIR MIXTURES •--Storage Conditions• •--Composition, gm. . Temp., R.H., Callus Sorbitol øC. Time Moisture Required Absorbed at to Reach Equilibrium, Equilibrium, % days 0 1851 0 2175 ß ß 0 1'•36 0 1425 0 1690 0 1738 ß ß 0 1'1'67 0 1066 ... 23 45 6.7 4 23 45 6.9 4 0.'•77 23 45 0.5 1 0.5243 23 45 0.5 1 0.3344 23 45 2.9 4 0.3250 23 45 2.4 4 ... 23 60 11.2 6 23 60 11.7 6 0.'1•'02 23 60 1.2 1 0.1493 23 60 1.1 1 0.1394 23 60 5.9 4 0.1793 23 60 5.2 6 * Lot #2, frozen, pounded. tentiates moisture pickup of unwashed callus but that the amount of water vapor absorbed is strictly an additive function. In other words, the observed water pickup of mixtures of callus and humectant is precisely that which would result by adding the moisture pickup of equivalent amounts of the two components exposed separately. In measuring the water uptake of propylene glycol and of mixtures of propylene glycol and callus, it was noted that these substances attained a peak water pickup after two days exposure. The weight then decreased and continued to decrease below the weight of the original anhydrous mixtures. Since the vapor pressure of propylene glycol is 0.15 ram. at TABLE 4--A COMPAKISON OF CALCULATED AND EXPERIMENTALLY DETERMINED MOISTURE SORPTION OF UNWASHED CALLUS -q- HUMECTANT MIXTURES -•Storage Conditions• Moisture Absorbed at •----Composition, gm..----, Temp., R.H., •-- Equilibrium, %----, Callus Humectant* øC. % Found Calculated• 0.1357 0.2852 G 23 45 13.5 14.9 0.1097 0.3077 G 23 45 14.6 15.7 0.0825 0.3193 G 37 40 14.2 14.6 0.1084 0.3134 G 37 40 13.2 13.9 0.0997 0.2335 G 23 60 29.6 30.2 0.0988 0.1924 G 23 60 28.2 29.2 0.1130 0.2486 G 23 90 129.0 132.5 0.1513 0.3397 G 23 90 129.0 133.0 0.1245 0.2952 PG 23 45 15.0 15.3 0.1417 0.2945 PG 23 45 14.3 15.0 0.1426 0.2149 PG 23 60 24.4 23.6 0.0952 0.1944 PG 23 60 25.4 25.2 0.1936 0.3344 S 23 45 2.8 2.9 0.1425 0.3250 S 23 45 2.4 2.5 0.1167 0.1394 S 23 60 5.9 5.8 0.1066 0.1793 S 23 60 5.2 5.1 * G = Glycerol, PG = Propylene glycol, S = Sorbitol. t Based on data shown in Tables 1, 2 and 3.