24 



SCIENCE 



[Vol. LV. No. 1410. 



hoi and crystallization liave been found in two of 

 the American made products. Experiments show 

 that this does not exert any untoward effect upon 

 the drug. A study of the colloidal properties 

 and the relationship to toxicity has also been 

 undertaken in order to explain the above "reac- 

 tions. ' ' 



Hydrogen peroxide, its manufacture and preser- 

 vation: Paul Poetschke. The quality of the 

 chemicals needed and the equipment required for 

 manufacturing the product and a detailed account 

 of the various stages of the process are given. 

 Briefly, the process consists in hydrating barium 

 peroxide wdth distilled water and adding this mix- 

 ture to a dilute solution of phosphoric acid which 

 forms barium phosphate and hydrogen peroxide. 

 Sulphuric acid is then added which regenerates 

 the phosphoric acid converting the barium phos- 

 phate into barium sulphate and phosphoric acid. 

 In this way the phosphoric acid is used over and 

 over again. The insoluble barium sulphate and 

 phosphate is then removed hj filtration and the 

 filtered hydrogen peroxide purified and adjusted 

 to the proper strength. Experiments with quinine 

 sulphate show that this substance has many ad- 

 vantages over acetanilid as a preservative, particu- 

 larly in that only 1/lOth the amount is required 

 and it does not cause any foreign odor or discol- 

 oration. A niixture of benzoic acid and salicylic 

 acid is also effective. Storage in glass bottles 

 of suitable quality, and exclusion of light, are far 

 more effective in restraining decomposition than 

 any of the preservatives studied. 



Developments in mercurial antiseptics: Edwin 

 C. White and Justina H. Hill. 



The preparation of certain arsenic-free rea- 

 gents: G. D. Beal and K. E. Sparks. 



The preparation of pure fatty acids: G. D. 

 Beal and J. B. Bbown. 



The preparation of cholesterol esters of fatty 

 acids: G. D. Beal and J. B. Brown. 



The determination of aldehydes in essential 

 oils: Eeancis D. Dodge. The use of bisul- 

 fite solutions in the technical determination 

 of aldehydes is sometimes inconvenient, ow- 

 ing to the relative insolubility of the bisul- 

 fite compounds. The writer has found the 

 solution of lithium bisulfite quite useful in such 

 eases, the lithium compounds being in general 

 more soluble than the sodium or potassium de- 

 rivatives. A serious error arises, however, when 

 unsaturated alcohols such as geraniol, linallol, or 

 terpineol are present. The latter react slowly 

 with bisulfite, yielding soluble sulfonic com- 



pounds and the aldehyde determination becomes 

 quite inaccurate. Details are also given of ex- 

 perimental work with some other aldehyde 

 reagents. 



Crystalline ethyldihydrocupreine (optochin) 

 base: Michael Heidelberger and Walter A. 

 Jacobs. Hitherto only crystalline salts of ethyldi- 

 hydrocupreine (optochin) have been reported. 

 Having found that dihydroquinine could be ad- 

 vantageously recrystallized from toluene, we dis- 

 solved ethyldihydrocupreine in this solvent and 

 allowed the solution to evaporate spontaneously, 

 crystals forming after several days. On seeding a 

 concentrated solution and letting stand the base 

 separated as irregular leaflets containing toluene 

 of crystallization, a portion of which was retained 

 on air-drying, but could be removed by heating 

 in vacuo. The base so obtained has approximate- 

 ly the properties of the purest commercial sam- 

 ples of the substance. 



Crystalline ethyldihydrocupreine (optochin) 

 hase: Michael Heidelberger and Walter A. 

 Jacobs. 



The purification of tulierculin and the prepara- 

 tion of ophthalmia tuberculin discs: M. Dorset 

 AND J. A. Emery. 



Food as a medicine: Harvet A. Wiley. 



The need for an improved formula for infusion 

 of digitalis, U. S. P.: A. Eichard Bliss, Jr. 

 In response to the complaints of clinicians con- 

 cerning the unreliability, lack of uniformity, etc., 

 of the Infusion of Digitalis of the U. S. Pharma- 

 copoeia, a pharmacodynamic study of twenty 

 samples of the Infusion was made. Fifteen of the 

 samples were collected at random from retail 

 drug stores, and five of the samples were pre- 

 pared in the laboratory according to the unoffi- 

 cial method advocated by Hatcher and Eggleston. 

 The method of pharmacodynamic assay employed 

 was that known as the Hatcher and Brody Cat 

 Method, a total of seventy-four estimations 

 being made by this method. Ten of the drug 

 store samples, prepared by the method of the U. 

 S. P. IX, showed an average activity of but 38.1 

 per cent, of the theoretical activity; five of the 

 drug store samples, prepared by diluting the 

 fluid extract, showed an average activity of but 

 62.6 per cent, of the theoretical activity'; and 

 the five samples, prepared according to the 

 method of Hatcher and Eggleston, showed an 

 average activity of 95 per cent, of the theoretic 

 activity. The dropping of tlie infusion as pre- 

 pared by the present IJ. 'S. P. method, or the sub- 

 stitution of an improved formula, such as that 



