EFFECTS OF GELATIN ON FINGERNAILS 449 TABLE III--ANALYSIS OF THE EFFECT OF GELATIN ON FINGERNAILS Subject Nail % Change in Hardnesst Observed Subject's Expression of Sam- 1 2 5 Improvement Improvement pie* Month Months Months (5 Months) (5 Months) B (Female) J (Male) K (Female) C (Female) I (Female) M (Male) R-1 +392 +578 +2397 Absence of R-3 -- 0-- -- 14 +56 peeling R-5 --45 -0-- +18 L-4 +112 +170 +351 Absence of R-4 +154 +231 +437 chipping and R-5 +229 +288 +163 breaking N R-3 +27 + 148 +68 (Female) R-4 +37 +100 +154 R-5 +83 +128 +144 L-3 +106 +52 +33 Absence of L-5 +98 +150 +41 peeling and R-5 +162 +112 +1472 chipping. Nails thicker L-5 --53 --49 --42 None R-4 +227 +198 +130 R-5 +598 +735 +14 L-4 +6 +88 +277 Reduction in L-5 --48 +19 +131 splitting R-5 --55 +26 +167 L-1 +26 +21 +39 Reduction in L-3 +28 +30 +51 chipping. In- R-1 +54 +106 +151 creased lus- ter Reduction in peeling Increased resistance to split- ting and peeling. Nails seem stronger Increased resistance to chip- ping and breaking. Nails seem stronger and more lus- trous, grow faster Increased resistance to chip- ping and peeling. Nails seem harder and grow faster Increased resistance to chip- ping Nails feel harder and show less splitting Increased resistance to chip- ping nails feel harder and grow faster Increased resistance to peeling and breaking. Nails feel harder and grow faster * L-1 = Left Thumb, L-2 = Left Index, L-3 = Left Middle, L-4 = Left Ring, L-5 = Left Little, R-1 = Right Thumb, R-2 = Right Index, R-3 = Right Middle, R-4 = Right Ring and R-5 = Right Little. t (+) = Increase in Hardness, (--) = Decrease in Hardness, and (0) = No Change in Hardness. In calculating the per cent change in hardness, expressed in Tables III and IV, all data were subjected to statistical evaluation using the chi-square method (7). A chi-square test is applicable whenever one or more differ- ences are compared with expectation based upon a hypothesis. We started with the negative hypothesis that there would be no change in hardness between those nails subjected to placebos and those subjected to the gelatin. A significant value of chi-square denotes a sample so discrep- ant as to bring into doubt the hypothesis set up any chi-square beyond 6.635 (a probability value of 0.01) is large and suggests rejection of the hypothesis. The larger the value of chi-square, the stronger the evidence against the hypothesis. In the data in Tables III and IV, the per cent change was recorded when the chi-square value was 6.635 or greater, and therefore considered signifi- cant the values were recorded as no change (0) when the chi-square value was less than 6.635. Tables I and II present the changes in hardness, expressed as Knoop Hardness Numbers, for the nails of subjects on the gelatin regimen and the placeb'o regimen, respectively. Each value shown is the average of three measurements made on a single nail sample.

450 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS In Table III is recorded an analysis of the data obtained with subject individuals on the gelatin regimen. Examination of the data in Table I reveals several significant observations. First, in all of the test subjects there was a significant increase in the hardness of the fingernail during the course of the study. Moreover, as indicated in Table III this increase can be seen to occur in five of the seven test subjects within a period of one month following initiation of the gelatin regimen. At the end of two months all of the subjects showed a significant increase in the hardness of their fingernails. However, at the end of five months Subjects K and C showed a softening effect. When surveyed both subjects stated that during the fourth and fifth months of this study they were "continuing to take the capsules but not as often." Noteworthy, as indicated in Table III, is the variation in the per cent increase in hardness in the nail samples of any one test subject. This is particularly significant in the case of Subject B. Also of importance is the relatively high degree of correlation of observed improvements in nail condition to the subject's expression of improvement. Table IV presents the analyzed data obtained with test subjects receiving placebo capsules. Although an initial increase in the hardness of the TABLE IV--ANALYSIS OF THE EFFECT OF PLACEBO CAPSULES ON FINGEP. NAILS Subject Observed Improve- ment Subject's Expression of Nail •---% Change in Hardness•--• (5 Improvement Sample 1 Month 2 Months 5 Months Months) (5 Months) R L-4 4.101 4-58 4-77 (Male) L-5 4-87 4-68 4.18 None No improvement R-5 4.143 4.117 4-75 Q L-5 -0- -12 (Male) R-3 -0-- --0-- -0- None No improvement R-4 --0- -0-- --16 P L-5 -0- -16 --25 (Male) R-3 4.12 -0-- --0-- None No improvement R-5 -19 -10 4-28 0 L-5 4.12 4-5 --10 (Male) R-3 4-26 --0-- --15 None Nails seem to grow R-5 +30 - 16 - 13 faster H L-5 --0- -0-- +19 (Male) R-3 --9 --9 --13 None Nails seemed smoother R-5 +9 +i4 --i6 E L-4 4-8 --0-- --7 (Female) L-5 q- 13 q- 8 -- 0-- None No improvement R-5 -11 --8 --8 D L-4 -0-- --0-- --0- (Female) I.-5 4-22 -0-- -0- None No improvement R-5 --0-- --0-- --0-- L L-3 --38 --38 --18 (Male) L-5 +8 --0- +12 None No improvement R-5 -0-- --28 --15 * L-1 = Left Thumb, L-2 = Left Index, L-3 = Left Middle, L-4 - Left Ring, L-5 = Left Little, R-1 = Right Thumb, R-2 = Right Index, R-3 = Right Middle, R-4 = Right Ring and R-5 = Right Little. •' (4-) = Increase in Hardness, (-) = Decrease in Hardness, (O) = No change in Hardness.