314 THE ANALYST. APPARATUS. Improved Extraction Cup. E. B. Warren. (Chem. Nezus, 1906, 93, p. 228.) -The essential feature of this cup is that the substance extracted is acted upon by the pure solvent, at the boiling-point of the latter, thus greatly facilitating the extractionof difficultly soluble sub- stances, such as Carnauba wax by acetone. Two forms are described, that shown in Fig. 1 having a discharge pipe from the bottom, which is carried upwards to a point below the top of the cup, allowing the residue to be dried in a stream of any gas, if liable to undergo change during drying in the ordinary way, while in Fig. 2 the cup containing the substance to be extracted is supported in a tube, and the solvent in the cup kept at a height corresponding to the height of the outer tube.The bottom of either cup is covered by a plug of wool, the material under examination weighed into it, and the cup placed in a flask, into which is poured the solvent. The flask is then attached to a reflux condenser so arranged that the condensed solvent falls back into the CUP, percolates through the material, and passes away through the outlet back into the flask. W. H. S. New Form of Absorption Tube. E. P. Perman. (Chenz. Xews, 1906, xciii., 213.)-This tube is devised to prevent any possible suck- ing back of the absorbing liquid into the generating flask during the estimation of ammonia, chlorine (from peroxides), etc. The long bulb C is 3.5 inches long and 1 inch in diameter; the bulbs B and D 1.25 inches in diameter, The liquid in C should just close the narrow tube a t E.A is connected with the generating flask by rubber, cork, or ground-glass joint, and a guard tube, containing glass beads moistened with the absorbent, may be connected to F. W. H. S. %+I+@** REVIEW. URIC ACID (the Chemistry, Physiology, and Pathology of Uric Acid and the Physiologically Important Purin Bodies, with a Discussion on the Metabolism of Gout). FRANCIS H. MCCRUDDEN. (New York : Paul B. Hoeber. Price: paper, $2.50 ; canvas, $3.00 net.) The work is a painstaking exposition of all that is at present accurately known as to the conditions of the formation and excretion of uric acid in the animal system. The references given to the literature of the subject are exceedingly copious, and mould appear to be exhaustive. The portion devoted to the purines is most instructive, and the whole work should be decidedly valuable to the physiological chemist.W. J. S,THE ANALYST. 315 ANALYSIS AND CONTROL OF MILK-SUPPLIES. (From the ((Chemist and Druggist” of June 16, 1906.) IN Section 8c of the International Congress of Applied Chemistry held in Rome a very interesting paper was read by A. Lane, of Rotterdam, on this subject. Ritherto the public has been protected from adulteration of milk to a great extent by the systematic taking of samples and assay of fat ” and (‘ other solids,” and the supply has in consequence vastly improved in those respects; but there still remains the fact that enormous volumes of milk are supplied for human consumption which conie from diseased cows. Tuberculosis is so prevalent that it will probably be demon- strated before long that the mixed supplies of milk from all the counties of England are tainted.Bacteriology fails to detect this except by animal inoculation, which, owing to the time involved and for other reasons, is impracticable. Very welcome, therefore, is any method leading to a, ready means of detecting diseased milk. By the ordinary routine of milk analysis it is often possible for grossly diseased milk to pass the standard, and yet it is vastly more important to the consumer that his milk should come from a healthy source than that he should be defrauded of 5 or 10 per cent. of the fat. The chief factor upon which the author depends is what he calls the (( oatalase number,” which is obtained by the introduction of 10 C.C.of the milk and 5 C.C. of hydrogen-peroxide solution into a fermentation-tube, and measuring the gas liberated by the catalase in the milk, which is increased in stale and diseased milk. I n his published analyses a most striking contrast is shown between the milk derived from different udders of the same cow suffering from parenchymatous mastitis. The disease was confined to one part of the udder, and the catalase number for that quarter was 6.6, while the healthy part yielded a catalase number 1.2 (healthy fresh milk being unity). The figures in many other diseased conditions are reported, both local in the udder and general. The author has also investigated the effect of milk from diseased cows upon the polarimetric reading, the degree of acidity, and the freezing-point, and his contention is that all these factors should be ascertained in judging a milk. His investigations lead him to the opinion that a lower reading than 4’ of the polarimeter, accompanied by a normal or slightly lowered freezing-point, indicates a milk from a diseased cow, and a catalase number above 3 indicates a decomposition advanced to such a degree that the milk should be considered unfit for human consumption. @ @ @ 4 @