BY making use of the data for the primary alcohols, acetates, n-fatty acids and ethyl esters described in the previous paper [Piper et al., 1934], and for the paraffins described in an earlier paper [Piper et al., 1931] we are now in a position to unravel the composition of the mixtures of alcohols, acids and paraflins which occur in insect and plant waxes. Francis et al. [1930] examined with the aid of X-ray analysis a series of acids isolated from natural sources, and were able to show that the so-called arachidic, lignoceric, cerotic and montanic acids wete mixtures of n-fatty acids, which accounted for the divergence of their melting-points from those of the pure synthetic acids to which they were supposed to correspond. In addition they were able to show by oxidation to the corresponding acids that the ceryl alcohol of Chinese wax and the melissyl alcohol of camauba wax were not chemical entities but mixtures of primary alcohols. In the present paper we are able to amplify a little the conclusions of these authors with regard to the naturally occurring wax acids and completely to unravel the constitution of a large number of wax alcohols. Examination of some thirty samples of these alcohols has shown that they are all mixtures, but in certain cases one particular alcohol predominates to such an overwhelming extent that we have been able to isolate it in a state of undoubted purity. Thus n-triacontanol has been isolated from lucerne leaves [Chibnall et al., 1933] and n-hexacosanol from blades of cocksfoot [Pollard et al., 1931]. n-Octacosanol has been prepared from the blades of wheat [Pollard et al., 1933]; in addition it was possible to show that at least three other alcohols were present in very small amount. The primary alcohol present in apple cuticle wax was shown, by fractionation of the derived paraffins, to be a mixture of the three above-mentioned alcohols [Chibnall et al., 1931]. In this particular case the important point was definitely established that the neighbouring odd-number alcohols, n-heptacosanol and n-nonacosanol, were absent. Finally cocceryl alcohol, which is the sole alcoholic component of cochineal wax, has been shown to be 15-keto-n-tetratriacontanol [Chibnall et al., 1934]. Since therefore all the