676 



SCIENCE 



[N. S. Vol. XXXVIII. No. i 



Olivee E. Closson : A Time Beoorder for Kymo- 

 graph Tracings. 



It is at best a tedious operation to find the pro- 

 jection of the time record on the different graphs 

 as ordinarily traced upon smoked paper. 



By the following simple device the time inter- 

 val can easily be recorded by a fine line, entirely 

 across the paper. 



A fine spring wire stretched two to three milli- 

 meters from the smoked surface will, when picked 

 by the armature of the time signal magnet, strike 

 the smoked paper on the rebound and remove a 

 fine line of soot. 



By a little adjusting a single distinct line is re- 

 corded at each closure of the circuit. If it is in- 

 convenient to adjust any recorder to write perpen- 

 dicular to the base line it is a simple matter to ad- 

 just so that the time line is parallel to any such 

 line. 

 Oliver E. Closson: Apparatus for Studying Oxi- 



The reaction of oxidases with hydrogen peroxide 

 liberates heat, and the temperature factor being 

 large as well as the expansion of the gas, all ne- 

 cessitate a thermostat control and continued agi- 

 tation of the mixture for comparative studies. 



To obtain uniform temperature and continuous 

 record of the liberated gas the following appa- 

 ratus was devised. 



A shaking member with two compartments, one 

 for holding the hydrogen peroxide and the other 

 for the enzyme solution, is connected by a tube 

 with ground joint to a large cylindrical container 

 with center at the axis of motion so that liquid in 

 this container is not agitated by motion around 

 the axis. This arrangement allows the shaking of 

 the reacting solution and the measure of the lib- 

 erated oxygen by the water displaced. 



The large container has a tube extending along 

 the axis to the outside of the thermostat, which 

 allows the discharge of the displaced water into a 

 vessel suspended by a spring, so that a writing 

 arm can be made to record the volume, giving on 

 a rotating drum a curve, which can be analyzed at 

 one's leisure. 



Amos W. Peters and Mary E. Turnbull: A 

 Method for Studying Slight Degrees of Glyco- 

 suria, Adapted from Macleod and S. B. Bene- 

 dict. 



Urine is clarified by the method of Macleod, i. e., 

 urine _[- concentrated acetic acid -\- Merck 'a blood 

 charcoal. No sugar is lost by this procedure, the 

 urine is diluted to only 7/5 original volume, the 



filtrate is water-clear for polarization. Five c.c. 

 of the filtrate, contained in a 100 c.c. Kjeldahl 

 flask, is neutralized with saturated solution of 

 Na^CO , using alizarine, and 5 c.c. of a modified 

 Benedict reagent is added. After placing a pebble 

 in the liquid and fixing the flask in an inclined 

 position directly over a small Bunsen flame the 

 w^hole is boiled for 2* minutes. The resulting 

 small volume is transferred to a centrifuge tube 

 and made to 10 c.c. Examined under a shaded 

 electric light and against a dark background even 

 a trace of dextrose shows turbidity, and after cen- 

 trifugation so little as 0.0035 per cent, shows a 

 film of red precipitate. Quantitative estimations 

 are made by comparison with standards based 

 upon a normal urine obtained under normal diet 

 and showing zero rotation, or nearly so, after 

 clarification, and to which dextrose is added in 

 steps of 0.01 per cent. The sensitivity is such that 

 pronounced differences result with these small in- 

 tervals. 



Composition of the above reagent: Sod. citrate 

 100 gm. ; sod. acetate 100 gm. ; sod. carb. anhyd. 

 50 gm. ; eryst. copper sulph. (Kahlbaum) 12.5 

 gm. ; dist. water add 500 c.c. 

 W. S. Hubbard and D. M. CowiE: A Method of 



Estimating Fat in Infant Stools. 

 S. L. JoDiDi: Nature of Humus and its Belation to 



Plant Life. 

 Philip Adolph Kober: The Estimation of Pro- 

 tein, Animo and Nucleic Acids in Potable 

 Waters. 

 William N. Berg: Surface Tension in Muscle 

 Contraction. 



Macallum quotes Jensen to the effect that ' ' a 

 thread measuring 1 millimeter in diameter formed 

 of the Plasmodium of Chondrioderma, a Myxomy- 

 cete, may, when it is in the dense condition, bear 

 up a weight of nearly a gram. If the force en- 

 gaged is surface tension it would amount to about 

 6,000 dynes per centimeter." 



At the same time Macallum does not quote 

 Pfeffer, who says that in the case of the Plas- 

 modium of Chondrioderma, the outer membrane 

 may vary reversibly, in its consistency, from that 

 of the fluid protoplasm in the interior of the cell 

 to that of solid gelatinous masses. 



Jensen obtained the figure of 6,000 dynes per 

 centimeter by dividing the weight sustained by the 

 Plasmodium thread by the circumference of the 

 thread. It would have been just as logical to di- 

 vide the weight sustained by a steel wire by the 

 circumference of the wire and call the equipment 

 the surface tension of steel. 



