OOTOBEB 7, 1910] 



SCIENCE 



475 



must not allow the use of unfit raw material; 

 it must be non-irritant; it must not retard the 

 action of the digestive ferments; it must be an 

 e6Scient preservative; it must not decompose into 

 more active substances than itself. Sodium ben- 

 zoate does not meet these requirements and its 

 use is attended with so many disadvantages that 

 it should not be allowed in foodstuffs. 



Following the general session the society met 

 as usual by divisions. The Division of Fertilizer 

 Chemistry and the Sections of Biological Chem- 

 istry, Chemical Education and Chemistry of India 

 Rubber held no meetings. Biological papers were 

 therefore presented before the Division of Agri- 

 cultural and Food Chemistry. Divisional meet- 

 ings were held on July 14, 15 and 16 with pro- 

 grams as follows: 



DmSION OP AGEICIJLTUEAI, AND FOOD CHEMISTET 



Tlie Sacoharimeter Scale and the Means of its 



Verification: C. A. Browne. 



The various standards for the saccharimeter 

 scale are described; methods of verifying scale 

 divisions of a saccharimeter by means of quartz 

 plates, the control tube and c. p. sucrose are 

 given. The author has recalculated the sucrose 

 values of the saccharimeter scale, using Landolt's 

 formula and shows that the maximum error due 

 to change of concentration is only 0.01° V. The 

 table of Schmitz which shows a maximum error 

 of 0.08° V. is erroneous. The statements of 

 manufacturers that the wedge surfaces of sac- 

 charimeters are plane and the scale divisions 

 equidistant are verified by practical tests upon 

 modern instruments. The maximum error of 

 graduation due to imperfections of quartz were 

 not found to exceed 0.05° V. upon two saccharim- 

 eters and were usually considerably within this 

 limit. The relation between the French and Ger- 

 man normal weights for sucrose according to 

 measurements made upon a Laurent " plaque 

 type" was 26 gms. to 16.29 gms., which agrees 

 with the weights officially prescribed in Germany 

 and France. 

 The Normal Weight of Dextrose: C. A. Bbowne. 



The normal weight of dextrose for a saccharim- 

 eter, using the Vcntzke scale, is given by differ- 

 ent authorities as between 32.5 and 33 gms., ac- 

 cording to the concentration of dextrose in solu- 

 tion taken as a basis of calculation. The author 

 believes that the weight of pure dextrose, which, 

 dissolved to 100 true c.c, will polarize exactly 

 100 at 20° C, should be taken as the normal 

 weight. The value thus calculated, using Tol- 



len's formula, is 32.25 gms. The actual dextrose 

 value of the scale divisions of the saccharimeter, 

 using this normal weight, is found by means of 

 a table or a fonnula, which is correct for varia- 

 tions in specific rotation due to concentration. 

 The advantage of using this method is that the 

 per cent, of dextrose is found at one operation 

 without the necessity of making a preliminary 

 assay of material to determine the exact quantity 

 necessary to be weighed out. 



On the Oxidation of Pyrogallol hy Hydrogen Per- 

 oxide in the Presence of Plant Extracts: H. H. 

 Bunzel. 



Evidence is given that the oxidation of pyro- 

 gallol to purpurogallin by hydrogen peroxide in 

 the presence of plant extracts takes place in two 

 stages. The first is carried on by the hydrogen 

 peroxide, the second by the oxidizing enzyme in 

 the plant extract. 



Detection of Lemon Oil in Orange OH: E. M. 



Chace and A. R. Albbight. 



The method employed depends upon the differ- 

 ence in the refractive indices of the aldehydes 

 contained in lemon oil and in orange oil. The 

 aldehydes are separated by formation of double 

 sulphite compounds, which are decomposed by 

 means of sodium carbonate and caustic soda under 

 ether. The ether is evaporated and the refractive 

 index of the remaining oil taken after drying and 

 thorough purification. It is found that the re- 

 fractive index of the aldehydes from lemon oil are 

 almost identical with citral, while the aldehydes 

 from both sweet and bitter orange oil are very 

 much lower. The method is only very roughly 

 quantitative. 

 The Influence of the Ingestion of Spices upon the 



Excretion of Hippuric Acid: H. E. Baenabd. 



It has long been known that hippuric acid 

 formerly found in the urine of man and in larger 

 quantities in the urine of the herbivorous animals 

 is produced by pairing of glycocol with benzoic 

 acid. The origin of the benzoic acid eliminated as 

 hippuric acid has usually been attributed to the 

 ingestion of plant foods, fruits, etc., in which 

 benzoic acid sometimes occurs naturally. 



It has also been stated that the ingestion of 

 spices containing essential oils of the aromatic 

 series induces the increased excretion of hip- 

 puric acid, and to determine this point the hip- 

 puric acid was determined in the urine of seven 

 subjects for four days, during which time the 

 subjects ate normal food, and later for seven 

 days when each subject was takinc a bottle of 



