THE SEPARATION OF PHOSPHATE ION IN QUALITATIVE ANALYSIS R . C. CANTELO, UNIVBRSITY OP CINCINNATI, CINCINNATI, OAIO .. Most courses in elementary qualitative analysis include a separation of Groups 3,4, and 5 in the presence of a soluble phosphate. In most schemes of analysis directions are given for the removal of the phospbate ion as femc, chromium, and aluminum phosphates from a solution which,contains acetic acid and ammonium acetate, i. e., from a solution containing a low concentration of hydrogen ion. The excess of iron added, over that needed stoichiometrically to combine with the phosphate ion is precipitated as basic femc acetate, and at the same time a part of the aluminum and chromium may also precipitate as basic acetates. The equations representing the reactions taking place are given as follows: FeClj Na2HPOd = hPOl + 2NaC1+ HCI FeCls 3NHGHaOn = Fe(CnHs0x)a 3NHdCI. When boiled,
+ +
Fe(CnHtOl)s
+
+ 2HOH = Fe(0H)nGHzOz + 2HGHaOl.
Similar equations may be written for the separation of aluminum and chromium. The precipitate obtained is large and bulky and the filtrate amounts usually to 350 to 400 cc., this necessitating an evaporation to a volume of about 30 cc. This method has been found unsatisfactory &y the writer's students when barium ion is present, and to a lesser extent when strontium ion is present. The inference is that the barium ion is adsorbed by the bulky precipitate described above. Unknowns containing barium have been unsuccessfully examined by students who have reported no difficulty when using the method now to be described. Baskerville and Curtman in their "Qualitative Analysis" make the statement: "Metallic tin, when added to a nitric acid solution of a phosphate, precipitates the phosphate as stannic phosphate, the excess of tin separating at the same time as insoluble metastannic acid. This reaction. . . . . .may be employed for the separation of the phosphate radical from the metals." The following procedure based upon the above reactions has proved most successful with elementary students in qualitative analysis. Evaporate to dryness the filtrrrte from the copper dnd tin groups. Add 5 cc. of concentrated nitric acid and again evaporate to dryness in order to remove all the hydrochloric acid present. Then add 25 cc. of dilute nitric acid and some c. P. granulated tin. This removes phosphate ion as insoluble stannic phosphate [Sns(POa)r]while the excess tin is precipitated
as metastannic acid. Heat gently for 10 minutes, then add 100 cc. water, boil and filter. Wash the precipitate well. The filtrate now contains the metals of Groups 3, 4, and 5 , while the precipitate is rejected. The filtrate may now be analyzed by any of the standard methods.
Syphilis Senun Tried in Germany. A new treatment for syphilis, using a preparation made from artificially cultured germs, is being tried a t the Kaiser-Wilhelm Institute for Experimental Therapeutics. Though the authorities caution against oversanguine expectations, they state that "the first results are wholly encouraging and give ~ccasionfor a thorough-going test of the new method." The development of the new treatment was made possible by the devising of a method for cultivating the germs of syphilis in test tubes in the laboratory. Efforts in this direction had hitherto not been very successful. Prof. H. Reiter of the Institute tried a fluid medium consisting of equal parts of normal salt solution and rabbit blood serum, with a small amount of rabbit or guinea-pig brain tissue added. In this he succeeded in getting an abundant growth of the spirochetes or germs of syphilis. Parts of these cultures. with the aerms urefullv killed, were injected into the skin . of children suffering from active syphilis and gave a very prompt reaction, though it had no effect on ~ a t i e n t swith latent forms of the disease. It was then tried on advanced u s e s of progressive paralysis, with encouraging results. German medical men are watching further progress of the tests with interest.-Science Sem'ce Science PiUs Dictionaries with Greek and Latin Words. The advance of science is changing language as well as modes of living. The classical origin of many of the words science is bringing into use is throying this element in the language into preponderance. Some 66 per cent of the real functioning w e d s in the dictionary today can trace their ancestry to Latin or Greek. Just the opposite was true fifty years ago, when the majority of words in common use were of Anglo-Saxon origin. Proponents of classical education have here a handy argument with which to bolster up the tottering hold of Greek and Latin on the curricula of present-day schools.-Science Service Vitamin Deficiency Studied Experimentally. Insight into the real mechanism of scurvy, beri-heri, and all the diseases caused by a lack of vitamins is the goal of a group of workers in the Hygienic Laboratory of the U. S. Public Health Service. In the Division of Pharmacology, M. I. Smith, W. T. McClosky, and E. G. Hendrick have been dosing devitaminized rats with various toxic drugs to see how the reaction of the avitaminous organism varies from the normal. How the functions of the different organs of the body are physiologically altered by a lack of vitamins is an aspect of the vitamin subject that has thus far received very little attention. These workers have found what might be reasonably expected-that the ability of the tissues of vitamin-deficient animals t o resist poisons is considerably reduced. The susceptibility of animals that have been deprived of vitamin A, which is necessary for health and growth, and the anti-neuritic vitamin B, to several nerve poisons indicates a general impairment of the nervous system. The markedly decreased resistance of vitamin A deficient rats to morphine suggests, according t o the authors, that the respiratory center is weakened by a lack of this essential food element. "Sluggish circulation and weakened respiratory center," say the authors, "would account satisfactorily for the frequent occurrence of pulmonary congestion and lung Service disease in rats an vitamin-deficient diet."-Science
