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knowledge the control of ventilation is largely empirical, and although this may be satisfactory for certain shapes and sizes of stock of which experience exists, the more general application of this method of control depends upon a detailed study of the subject. Fig. 6 resembles Fig. 5 in lay-out but refers instead to a 2-m. column of bag material impregnated with palm-kernel fat. A general comparison of the two Figures shows that the shorter column of bag material has a heating tendency of the same order as that of the longer column of kernels. This reflects the greater reactivity toward oxygen of the bag material.A study has been made of the pectin-demethylating enzyme system in apple tissue and the level of activity compared with that in some other fruits. The apple varieties tested show considerable differences in their pectase content, The enzyme shows a maximum activity a t pH 0.6 : over the pH range of the fruit the activity is much lower, but the enzyme can still produce appreciable effects. Methods for the extraction and concentration of the enzyme are described. The concentrated enzyme preparations are readily inactivated by normal pasteurizing temperatures (68-70" c.), but in juices the enzyme shows a much greater stability. The significance of these findings is discussed in relation to the production of apple juice and pectin.

IN the present paper an account is given of an investigation into the wax constituents of two very commonly occurring foliage grasses, cocksfoot (Dactylis glomerata) and perennial ryegraos (Lolium perenne). It has not been found possible to obtain as complete an analysis as that recorded in the previous paper dealing with apple-peel wax, but the results are of great interest because they have enabled us to investigate the constitution of a long-chain primary alcohol which is the main constituent of these two waxes.This alcohol has been shown to be a fairly pure sample of n-hexacosanol. Although this substance has been assumed to be present in many natural waxes and given the name of ceryl alcohol, evidence is produced that all the samples so far recorded in the literature are mixtures which may or may not contain n-hexacosanol.No paraffin was found in the cocksfoot, although a small amount was present in the ryegrass. This had M.P. 660. The literature contains many references to paraffins melting at this temperature, and from a similarity of melting-point they were always considered to be n-triacontane C30H62. We shall discuss paraffins of this type more fully in a later paper dealing with many samples of paraffins isolated by previous workers,who have very kindly placed samples of their products at our disposal for further analysis. In the present case it was quite easy to show that the paraffin, M.P. 660, was a mixture.It is shown in the discussion later that the hippocoprosterol of Bondzynski and von Humnicki [1896] and also of Doree and Gardner [1908] is the so-called ceryl alcohol. The latter authors also show quite conclusively by feeding experiments that hippocoprosterol passes through the intestines of herbivorous animals unchanged. One can conclude therefore that the n-hexacosanol found in cocksfoot and perennial ryegrass, which may be present to the extent of 1 % of the dry weight of the grass, has no feeding value.