141 THE ANALYST. AUGUST, 1870. THE COMPOSITION OF DEVONSHIRE CREAM. BY A. WYNTER BLYTH, lI.Rm.C.S., &.C. Read bl.forc tlie Society of Public Afralysts, on 4th J I I ~ C , 1879. I HAYE recently been studying the coiiipoSition of the sul>stance linown as Devonsliiro cream, and find the average composition as follows :- per cent. Water . . . . . . . . . . . . . . . . . . . . . . 28.675 Caseine .. . . . . . . . . . . . . . . . . . . 3.630 Albumin . . . . . . . . . . . . . . . . . . . . -521 Galactine . . . . . . . . . . . . . . . . . . . . -060 Lactoclironie . . . . . . . . . . . . . . . . . . . . Ciideteriiiined Milk Sugar . . . . . . . . . . . . . . . . . . . . 1.723 Milk Fat . . . . . . . . . . . . . . . . . . . . 65.011 Ash . . . . . . . . . . . . . . . .. . . . . . -493 Chlorine in Ash . . . . . . . . . . . . . . . . . . -013 Calcic Phosphate . . . . . . . . . . . . . . . . . . ,373 It will thus be seen that tlie mill; lins thrown up caseiiie with the fat, for if we allow that ordinary milk contains 86.87 of water niid 3-98 per cent. of caseine, then the amount of caseiiie in tlie cream, if none were selmrated, ~ ~ o n l i l be- Water.Caseine. Water. Caseine. 86.87 : 3.98 : 28.G75 = 1.31 But tlie cream instead of coiitainhig 1.31 per cent. actually contains 2-25? in excess of this quantity. The amount of ttlbumiii follows strictly tlie caseine, for if we allow, as I have elsewhere affirmed, that the average percentage of albumin in milk is 077 per cent., and therefore the ratio of caseiiie to albumin as 3.98 is to -77, then tlie tlieoretical yield of albumin in this particular case would be -66, the amount actually found being about -1 per cent.lower than this estimate. If tlie compositioii of the Devoii cream shows clearly that there is some consicler- able separation of the caseine, the milk sugar follows very closely tlie proportions one would expect to find from the amount of water for taking tlie average of 4.0 of milk sugar dissolved in 86.87 of water, then in the present case- Water.Sugar. Water. Sugar. 86.87 : 4.0 : 28.7 = 1.3 Which does iiot deviate very considerably from the numbers actually obtained, viz., 1.723. Pursuing the ratios still farther it will be noticed that the galactine also follows the same law, for if the number I have elsewhere given as tlie average percentage of this body in milk, viz., -17, be tnBen, then Water.Galactine. Water. Galactine. 86.87 : '17 : 28.67 = ,056142 THE ANALYST. Aiid s o 5 0 is tlie iiunzber experiment lias yielded. Similarly tlie percentage of ash, which alvays depends upon t w factors-one, the caseiiie ; and two, tlie amount of water-may be similarly proved to agree closely with tliat which theory ilemctiicls. The aiialysis of Devon or any other cream presents but little difficnlty : a weighed portion is taken, tlie fat melted, a d nft9r ahout half ail hour’s exposue to the heat of a water-bath, most of tlie cmeiiie, kc., settles to tlie bottom, and tlie fat can be poured off as easily as tliat from butter.Tlie residue remaining is now treated with petrolenm and tlioronglily exhausted. Tlie ftxt ” niid L‘ solids not fat ” are dried separately, mliicli indeed is the oizly w y in wliicli the water can with any coiiveiiicnce be estimated. With regard to the estimation of the other constitneizts, I have notliiiig new to &ad,