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Methods arc described for the routine estimation in ground scaweed saxr.plcs of mannitol by periodate oxidation, of alginic acid by isolation and the displacement of acetic acid from calcium acetate, of laminarin by hydrolysis to glucose and its estimation with the Shaffcr-Somogyi reagent, and of fucose (after hydrolysis) by periodate oxidation and estimation of the liberated acetaldehyde.Mannitol, alginic acid, laminarin, fucoidin and " algal cellulose" are the main organic constituents of the brown seaweeds (Phaeophyceae), and mcthods For their determination have been studied as part of the programme of research and development on seaweed undertaken by the Scottish Seaweed Research Association.-Earlier methods of analysis suitably adapted to the complex mixtures round in these alga: have, in the main, been used and, where possible, separation of the particular ,constituent before analys!s has been avoided in order to eliminate time-consuming operations. All estimatiom were carried out on seaweeds which had been dried and ground, and contained less than IO%, or' water, for which due allowance was made in the results. MannitolTwo methods were considered possible I'or the romine estimation of mannitol in seaweed, the first based on the quantitative extraction by a suitable solvent such as ?t-butanol, and the second involving the use of periodic acid.Extracfioit iwthod.-The sample of ground scaweed is extracted continuously in a Haanen and Badum apparatus with a boiling solvent, the most satisfactory round being ti-butanol, and the mannitol which crystallizes on cooling is filtered and weighed, the solubility in cold butanol being low (c. 0.015 g./roo cx.) compared with that at the boiling point. After several extractions by this method, almost complete removal oF mannitol is achieved, but it is unsuitable for routine estimations, especially : or samples o.f low mannitol content, since at least four extractions of 10-12 hours each are necessary. The method has been used, however, as a check on the periodic acid method.Periodic acid irIefhod.-hlalapradel has shown that mannitol (I mol.) requires 5 mol. of periodic acid : or complete oxidation.The amount of periodic acid used can be determined by titration with sodium thiosulphate after the addition of potassium iodide and sulphuric acid and comparison with a blank. The quantity of mannitol oxidized in 60 seconds was found to be 92% oT the total and the method was based on this rapid reaction. Esperiitiental procedurePilof experbrent.-To the sample (0.1 6.) ground to pass a Ioo-mesh sieve, sulphuric acid (5 c.c.; N/IO) and periodic acid (5 C.C. ; hl/Io) are added. A h exactly one minute potassium iodide (2-3 g.) and dilute sulphuric acid (20 C.C. ; 4 N.) arc added and the liberated iodine titrated to starch with sodium thiosulphate solution (N/Io). A blank is carried out simultaneously.Since gHIO, + 35HI = 2 0 1~ + 2oH,O and jH103 + 20H1 = 1512 + 15H20 I g. mol. mannitol Z 51, = 10 1. N-Sodium thiosulphate. Using the titration figure and a factor of 100193 (see below...

These findings are in keeping with those of Schmidte and HerzheimlO who failed to confirm any effect on undernourished children, but are contrary to those communicated privately by the Pharmazell Co. where rats that failed to grow and eventually lost weight and died on a purified diet grew moderately when vitamin T was added. The quantity of vitamin T used in the Pharmazell experiment was 0.6 ml. per day (corresponding to 840 ml. per 70-kg. adult), compared with 0.25 ml. in the second experiment.

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