692 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS as a plot of mean percentage of total ether-soluble material versus number of extraction cycles. Extraction Table VII Total no. cycles 25 5O 75 100 125 150 175 200 225 Subject 1 Extract i Cumulative % extract 3.72 3.72 0.62 4.34 0.26 4.60 0.15 4.75 0.08 4.83 0.00 4.83 Sub • Extract 5.60 0.33 0.26 0.41 0.02 0.09 0.07 0.02 0.02 ect 2 Cumulative •o extract 5.60 5.93 6.19 6.60 6.62 6.71 6.78 6.80 6.82 These results indicate that although 25 extraction cycles with ether remove about 80% of the ether-soluble material from hair, complete removal of ether-soluble material is not found until the number of extraction cycles is more than 100. (b) Methylene chloride A sample of hair was extracted successively with portions of methylene chloride (150 ml) using 25 cycles at 32-35øC (600 mm pressure) per extraction. The quantities of hair lipid obtained were 3.28% and 0.12% respectively for two extractions (Fig. 3). To check whether any ether soluble material was left on the hair the sample •vas then extracted with ether, when it was found that the quantity of hair lipid obtained was negligible (0.04%), indicating that the ether-soluble material had been removed by the methy- lene chloride extractions. (c) Ethanol A blended sample of hair was split into two portions and these were sequentially extracted as follows:- Portion 1 (a) (b) (c) (d) Portion 2 (a) Ether, 25 cycles at 32-35øC (atmospheric pressure) Methylene chloride, 25 cycles at 32-35øC (600 mm pressure) Ethanol, 25 cycles at 32-35øC (100 mm pressure) Ethanol, 25 cycles at 32-35øC (100 mm pressure) Ethanol, 25 cycles at 32-35øC (100 mm pressure)

THE EXTRACTION OF FATTY MATERIALS FROM HAIR CLIPPINGS 693 (b) Ethanol, 25 cycles at 32-35øC (100 mm pressure) (c) Ethanol, 25 cycles at 32-35øC (100 mm pressure) (d) Ethanol, 25 cycles at 32-35øC (100 mm pressure) The quantities of the materials obtained using the two extraction pro- cesses are shown in Table VIII the extraction with ethanol only is com- pared with the extractions with ether and methylene chloride in Fig. 3. Table VIII Extraction procedure (a) (b) (c) (d) Portion 1 Extract 2.67 1.05 0.67 0.03 Cumulative % extract 2.67 3.72 4.39 4.42 Portion 2 Extract 3.18 1.06 0.09 0.09 Cumulative •o extract 3.18 4.44 4.53 4.58 The results in Table VIII and Fig. 3 indicate that if ethanol alone is used (portion 2) then some 75 cycles are required for removal of the hair lipid whilst if it is used after ether and methylene chloride (portion 1) then only 25 cycles are required. This suggests that the best order of use of solvents (from the point of view of time and convenience) would be ether, followed by methylene chloride and then ethanol. (In our experimental procedure it was found that ether extraction took about 2-3 mins cycle -• methylene chloride extraction 4 mins cycle -•, and ethanol extraction 12-15 mins cycle -• Equivalence of ether and methylene chloride extracts The results given previously indicate that after extraction of hair with methylene chloride there is little if any ether-soluble material left. In addition, if a sample of hair is extracted with ether for 150 cycles and then extracted with methylene chloride, no lipid is obtained. This suggests that the 20% of ether-soluble material left on hair after 25 extraction cycles with ether (Fig. 3) is methylene chloride-soluble material. If this is so, then it is reasonable to expect that the material removed by say 100 cycles with ether is very similar to that removed by 25 cycles with methylene chloride. To examine this point the following experiment was carried out: A blended sample of hair was split into two portions and these extracted as follows:-