538 EXPERIMENT STATION RECORD. 



finely chopped material in sulphuric acid (specific gravity 1.820 to 1.S25) and water 

 1:1. The minutiae of the method arc described. 



A comparative refractometer scale for use with fats and oils, A. E. Leach 

 and II. C. Lythgoe {Jour. Amer. Chem. Soc, 26 [1004), No. 10, pp. 1193-1195, 

 Hi/. 1).—A slide rule fin - use in reading indexes of refraction with the Zeiss butyro- 

 refractometer is described. According t < > the authors "readings may lie obtained 

 on the scale of the butyro-refractometer at different temperatures without first 

 transforming them into indices of refraction; readings in indices of refraction maybe 

 obtained at different temperatures without calculation, and readings on either refrac- 

 tometer scale may be readily transformed into readings on the other." 



The iodin number of several fats and waxes determined by the Wijs method, 

 H. L. Visser {Ztachr. Untersuch. Nahr. ". Genussmtl.,8 (1904), No. 7, p. 419). — Among 

 other materials lard, cocoa butter, nutmeg butter, wool fat, yellow wax, Japan wax, 

 cocoanut fat, almond oil, linseed oil, castor oil, and olive oil were examined. 



Apparatus for determining- the melting point of resistant substances, 

 F. Kitsch kr and Otori (Ztschr. Physiol. Chem., 42 (1904), No. 3, pp. 19.], 19,}, Jig. 1).— 

 In the apparatus described, the thermometer is inserted in a test tube contained in a 

 long-necked quartz-glass flask. The authors consider that this form of apparatus is 

 especially satisfactory as there is no liquid in the flask and unpleasant results from 

 breaking are thus done away with. 



The identification of yeast extract in meat extract, M. Wintgen (Arch. 

 Pharm., 242 (1904), No. 7, pp. 537, 538). — The proposed method depends upon the 

 observed differences in the clearness of the solution when the proteids are salted out 

 with zinc sulphate in the determination of alhumoses by Bomer's method. 



A new method of estimating cellulose quantitatively in foods and feces, 

 0. Simon and H. Lohrisch (Ztschr. Physiol. Chem., 42 (1904), No. 1-2, pp. 55-58). — 

 The principle upon which the method descrihed is based is that although cellulose is 

 insoluble in 50 per cent potassium-hydroxid solution it may be dissolved if hydrogen 

 peroxid is also used and then precipitated quantitatively from the solution by alcohol. 



In practice, 10 gm. of dried material is treated with 50 per cent potassium-hydroxid 

 solution for an hour on the water bath at 100° C. and allowed to cool. Three or 4 

 cc. of hydrogen peroxid is then added, which breaks the incrusting cellulose cell 

 walls and brings the lignin and pectin into solution and at the same time acts as a 

 bleaching agent. If any material remains undissolved it may be brought into solu- 

 tion by again heating on a water bath 30 to 45 minutes. 



The cellulose is precipitated with 96 per cent alcohol. When the alcohol does 

 not mix with the alkaline liquid it is advisable to add 6 or 7 cc. of concentrated 

 acetic acid. After filtering through a hardened filter the cellulose is brought into a 

 beaker glass, washed with an abundance of water, filtered on a weighed filter, washed 

 with water, dilute acetic acid, alcohol and ether, dried and weighed. 



Critical and experimental studies on the calorimetry of urine, K. Farkas 

 and M. Kobbuxy (Arch. Physiol. [Pfluger], 104 (1904), No. 9-12, pp. 564-607).— -The 

 authors find that when aqueous solutions of urea are dried with or without the addi- 

 tion of hydrochloric acid or sodium carbonate a loss of energy is sustained. The loss 

 of energy is least when the solution is evaporated in vacuum at ordinary room tem- 

 perature without added material. The addition of hydrochloric acid hinders a loss 

 of nitrogen but not of energy. The relation between nitrogen and energy losses is 

 not constant. 



The use of cellulose blocks for absorbing and drying urine in the authors' opinion 

 is in most cases unnecessary and involves error except when the ash content is very 

 high. Small amounts of the dry matter of human urine or that of animals will burn 

 in the calorimeter completely without the addition of any other substance. Adding 

 hydrochloric acid or oxalic acid is unnecessary. The loss of nitrogen is parallel to 

 that of energy, though no fixed relation between the two could be pointed out. The 



