ASSIMILATION OF INGREDIENTS BY MICROORGANISMS 857 ++ + ++1 ++ ++ I ++• ++ +1 + ++1 ++ +• + ++1 ++ +• I +++ ++ +++• ++ I ++• ++ +++ I I I I I I +qq I ++ I ++ ++• I I I I I I ++ + +++ ++ ++++qq I I I I +-• + +++ ++ ++4--• qq I I I I ++ I ++ I ++

858 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS DISCUSSION OF RESULTS The results of the utilization of materials for growth by the various microorgamsms are shown in Tables III-V. Table VI shows the assimi- lation rate of the substrates studied. On the assumption that a material having an assimilation rate (AR) of over 0.5 can be easily utilized, it can be noted that about half of the tested materials were easily utilized by the organisms as the sole carbon source. These materials were liquid paraffins, oleyl alcohol, stearyl al- cohol, propylene glycol, isopropyl myristate, 2-hexyldecyl adipate, oleic acid, and stearic acid. It can also be seen that materials with an AR close to zero were not utilized by the microorganisms. These were solid paraffin, multiwax, camellian, squalane, silicones, hexyldecyl alcohol, di(2-hexyldecyl) adipate, and polyethylene glycol. Table VI Number a of Organisms Utilizing Materials Tested Bacteria Yeasts Fungi Substrates (23 Strains) (25 Strains) (17 Strains) AR b L.P.-1 9 24 9 (4) 0.65 L.P.-2 8 24 6 (7) 0.59 V 6 17 4 (5) 0.42 S.P. 7 3 I (2) 0.17 M.W. 5 0 (3) 0.08 Cam. 0 0 0 0 S.Q. 0 I (1) 0 o. 02 KF-96 0 0 0 0 KF-56 0 0 0 0 O1-A1 7 25 14 (3) 0.74 St-A1 6 19 5 (9) 0.46 HDA 0 0 0 P.G. 8 18 8 (2) 0.52 PEG-400 0 0 0 0 IPM 12 25 17 0.83 E-103 8 14 15 (2) 0.57 IPA 6 6 4 (3) 0.25 E-201 (1) 0 0 0 O1-Ac 8 25 17 0.77 St-Ac 10 24 17 0.78 • ( ) indicates strains showing slight growth. Total of growing strains b AR = Total of strains tested