5O JOURNAL OF THE SOCIETY values which are reported in the table. Also, at the ends of periods of incubation for thirty minutes, determinations of levels of pH of all preparations were made. The values for pH reported in Table 6 are the averages of the pH levels determined for the three preparations made up from any one aliquot of the benzyl mercaptan mixture with water. Comparisons of the pO values reported for the preparations iden- tified by subscripts "1" with the corresponding results for both the negative control and the A• prepara- tion indicate that the buffer solu- tions per se had no more effect upon intensities of odors of the benzyl mercaptan than did equiv- alent volumes of water. Hence, any changes in pO values of the preparations designated by sub- scripts "2" and "3" are attributable to the sodium-copper chlorophyllins which were incorporated in the buffer solutions. There is evident a dependence of the deodorant capacity of the chloro- phyll upon the balances between acids and bases in the liquid phases of the preparations to which it was added. At levels of pH below 6.0, capacities of chlorophyll to deo- dorize benzyl mercaptan decline markedly whereas in preparations having favorable balances of base over acid, the sodium-copper chloro- phyllins effectively eradicate the odor of benzyl mercaptan. A particularly significant finding in this series of experiments was the fact that increasing the alkalinities OF COSMETIC CHEMISTS of preparations from pH = 8.04 to pH = 10.50 failed to influence the deodorant efficiericies of chloro- phyll. In fact, in supplementary series of tests, it was observed that buffering comparable preparations at pH levels of 12.50 did not en- hance the deodorant efficiencies of chlorophyll above those deter- mined at levels of pH = 8.00. In other words, increasing the hy- droxyl ion concentration by more than 10,000 times did not augment the deodorant properties of chloro- phyll. On the other hand, in- creasing the hydrion concentration only 1500 times reduced the deo- dorant efficiency of chlorophyll by 50 per cent, as calculated from pO values. In brief, acidity, deter- mined as concentrations of hydrions in the liquid phase of the medium into which chlorophyllins are in- troduced, is the variable of primary importance as a determinant of their deodorant efficiencies. Several subsequent series of ex- periments were undertaken with the objective of ascertaining the in- fluences of hydrion concentrations, within more limited ranges of pH levels, upon the deodorant proper- ties of chlorophyllins. Results of these studies indicated that the hydrion concentration which was critical for inhibitions of deodorant actions of the chlorophyllins was indicated by a pH = 5.30 4- 0.30. This result represents an average of tests• of combinations of either sodium-copper or sodium-magne- sium chlorophyllins in concentra- tions of 500 rag. per 100 c.c. in

TESTING DEODORANTS WITH CHLOROPHYLL AND DERIVATIVES 51 liquid phases in which the sources of odor were (a) amines, (b) low molecular weight fatty acids as well as their esters and salts, (c) mer- captans and other organic sulfides, and (d) indol, skatol, and pyridine. The fact that within this narrow range of hydrion concentration significant reductions were demon- strable in the capacities of the chlorophyllins to eradicate odors from a variety of sources suggested that the critical hydrion concentra- tion affected chlorophyllins and not the odorous compounds. This hy- pothesis was confirmed by results of a series of tests directed to the objective of correlating solubilities of the chlorophyllins with their deodorant actions. In general, the experimental procedures were simi- lar to those adopted in the experi- ments summarized in Table 6. The sole modification of the tech- nique comprised the filtrations of the buffer solutions containing the chlorophyllins and then carrying out comparative analyses of the tiltrates for concentrations of chloro- phyll and, also, testing the deo- dorant capacities of both tiltrates and of the insoluble residues of chlorophyll. Results of these tests provided evidences of dependencies of both solubilities and deodorant capacities of the combination of the chloro- phyllins upon concentrations of hy- drions within approximately equiv- alent ranges of pH of preparations in which water constituted 90 per cent of the total volumes. Signifi- cant decreases in solubility of the chlorophyllins were observed at levels of pH = 5.70 4- 0.20 and precipitations of these chlorophyll derivatives were complete at hy- drion concentrations indicated by pH = 4.50. The findings in this group of experiments pointed to the conclusion that reductions in deo- dorant capacities of the chloro- phyllins, even in weakly acid ,olu- tions, were attributable to decreases in solubilities of these chlorophyll derivatives. The foregoing discussions of the dependencies of deodorant efFicien- cies upon acid-base balances of the liquid phases of sources of odors have been limited to results of tests of sodium-magnesium and sodium- copper chlorophyllins. No refer- ence has been made to either natural chlorophyll or the acid digest of chlorophyll. The reason for omitting the latter two products from these discussions is obvious. Neither natural chlorophyll nor the acid digest of chlorophyll is soluble in water. Hence, in aqueous solu- tions, except at high levels of alkalinity (at pH = 9.00 or more), they exhibit no deodorant actions. The three subsequent series of experiments were selected for pres- entation in Charts IV to VIII in- clusive for purposes of exemplifying in-vivo methods of evaluating deo- dorants. The objectives of the first two of these series of experi- ments (Charts IV, V, and VI) were the determinations of efFicien- cies of topical deodorants whereas the final series was directed pri- marily to an exploration of the