612 EXPERIMENT STATION RECORD. [Vol.35 



was found, however, only in fully ripe fruits. In pears the amount was found 

 to increase gradually until a maximum was reached in the overripe stage of 

 the fruit. The presence of aldehyde was only occasionally demonstrated in 

 upples, and in one sample of grapes examined was absent. 



The urease content of certain beans, with, special reference to the jack 

 bean, J. G. Mateee and E. K. Mabshall, Jk. (Jour. Biol. Chem., 25 (1916), 

 No. 2, pp. 297-305). — The authors have demonstrated that the jack bean 

 (Canavalia ensiformis) contains about 15 times as much urease as the soy 

 bean. The extract from the jack bean, however, contains much less solid 

 residue than the soy-bean extract. The urease appears to be specific for urea, 

 just as is the enzym obtained from the soy bean. The use of the jack-bean 

 urease for the rapid removal of urea from solutions in which as little contami- 

 nating material as possible should be added, and its use for quantative urea 

 determinations is indicated. The presence of urease was also established in 

 the urd bean (Phaseolxis aureus) and the horse gram (Dolichus biftorus). 



Notes on collodion membranes for ultrafi^ltration and pressure dialysis, 

 G. S. Walpole (Biochcm. Jour., (1915), No. 2, pp. 284-297, figs. 5).— This 

 article describes the preparation of collodion test-tube shaped bags and their 

 use for simple ultrafiltration and dialysis experiments. On account of their 

 lack of uniformity and the difficulty of accurate reproduction their use is not 

 recommended for careful work. 



Flat membranes are prepared by pouring alcohol-ether solutions of collodion 

 on leveled plate glass and then plunging the film, after partial evaporation of the 

 alcohol and ether, into water. With proper precautions films of remarkable 

 uniformity can be prepared. It is suggested that " in these films, more than 

 in other ultrafilters in general use, the channels leading through the gel struc- 

 ture from one side to the other are of a certain uniformity in size. None of 

 them is large enough to allow any antigen to pass ; but the structure is highly 

 porous and, because there are many such channels, rapid ultrafiltration results." 



The arrangements of apparatus in which the flat membranes and also the 

 test-tube shaped membranes can be utilized for ultrafiltration and pressure 

 dialysis are described in detail. 



A rapid filter for turbid liquids, R. C. Shuey (Jour. Indus, and Engin. 

 Chem., 8 (1916), No. 6, p. 523, fig. 1). — An ordinary suction filter, using the 

 paper pulp used by distillers, and its manipulation are described. 



A rapid method for comparing the decolorizing efficiency of charcoals, 

 L. WiCKENDEN and J. W. Hassler (Jour. Indus, and Engin. Chem., 8 (1916), 

 No. 6, pp. 518, 519, fig. 1). — A method which is rapid and enables charcoals to 

 be classified with great ease and accuracy according to their decolorizing effi- 

 ciency is described. A solution of Soudan III or Oil Red RN in kerosene is 

 used for the test. The solutions filter rapidly and come through clear and 

 bright. The preparation of a standard scale for classifying the charcoals and 

 also a simple colorimeter which facilitates the procedure are described. 



A new colorimeter, C. F. Sammet (Jour. Indus, and Engin. Chem., 8 (1916), 

 No. 6, pp. 519-521, fig. 1). — The author describes a colorimeter which is easily 

 adjusted. Although designed for reading the color of turpentine, it is equally 

 well adapted for other colorimetric work when standard glasses can be em- 

 ployed and the solution does not attack the metallic cell. 



A Kjeldah.1 fume remover, F. G. Meekle (Jour. Indus, and Engin. Chem., 

 8 (1916), No. 6, pp. 521, 522, figs. S). — An apparatus consisting of a lead pipe 

 of 0.5 in. inside diameter, to which are soldered as many 3-in. lead tubes (i in. 

 diameter) as desired, is described. The small tubes are fitted with rubber 

 stoppers, which are in turn fitted to the flasks used in the digestion. The acid 



