458 



SCIENCE 



[N. S. Vol. XXV. No. 638 



On the Excretion of Barium: Gustave M. 

 Meyer. 



On Alka/verdin, the Coloring Matter of 

 the Purple Pitcher Plant, Sarracenia 

 purpurea: Gustave M. Meter and Wm. 

 J. Gibs. 



The carefully selected leaves of the plant 

 were cut and dried, and then extracted 

 with 95 per cent, alcohol. The alcoholic 

 extract was concentrated by evaporation, 

 with repeated additions of water to pre- 

 cipitate the chlorophyl, then filtered and 

 finally evaporated under reduced pressure 

 at a low temperature. Heating the alco- 

 holic solution seemed to have little effect 

 on the pigment, but continuous heating in 

 the presence of considerable water caused 

 chemical alteration of the coloring matter. 

 The residue thus obtained is a perfectly 

 clear, red, resinous mass, soluble in water, 

 but insoluble in absolute alcohol and in 

 ether. It could not be induced to crys- 

 tallize. The substance is free from ni- 

 trogen. The aqueous solution reduces 

 Fehling's solution and yields glucosa- 

 zone with phenylhydrazine. With ben- 

 zoyl chloride a bulky benzoyl derivative 

 was obtained. Dilute aqueous solutions 

 are changed in color by acids and alkalies. 

 Alkali produces a deep green, acids dis- 

 charge the color. This indicator can be 

 used for acidimetry and alkalimetry under 

 conditions similar to those that apply to 

 litmus. The decided change from the 

 green to colorless condition on the addition 

 of acid is, however, far more delicate than 

 the change of litmus from blue to red 

 under similar circumstances. The delicacy 

 of this indicator is not affected by the pres- 

 ence of neutral salts. 



On the Formation of Sugar from Amino 



Acids: Wm. Salant. 



Experiments carried out on rabbits in 

 which phlorhizin diabetes was induced,, 



have shown that glycocoll administered 

 subcutaneously or by mouth is not followed 

 by an increased elimination of sugar. 



A Biological Method for the Detection of 

 Fluorides in Food Products: S. Amberq 

 and A. S. Loevenhart. 

 Loevenhart and Peirce have recently 

 shown that sodium fluoride even in very 

 minute quantities greatly inhibits the 

 hydrolysis of esters of the lower fatty acids 

 by extracts of different animal tissues. 

 The effect of a large number of other sub- 

 stances representing widely differing 

 classes of compounds on the hydrolysis of 

 the esters has been studied, with the result 

 that no other substances have been found 

 which have an inhibiting effect comparable 

 in extent with that shown by the fluorides. 

 Ammonium fluoride and hydrofluoric acid 

 act quite similarly to sodium fluoride. It 

 occurred to us that a simple and delicate 

 test for fluorides might be founded on 

 these observations. Clear liver extracts 

 were prepared by the method of Loeven- 

 hart and Peirce and the activity of 1 c.c. 

 of this was tested by diluting with 4 c.c. 

 of water and adding 0.26 c.c. of ethyl 

 butyrate and toluene. After acting for 

 16 to 24 hours at 35° to 40° the increase 

 in acidity was determined by titration with 

 N/20 NaOH. Simultaneously with the 

 above test, experiments were performed in 

 which the filtrates, neutralized if not 

 already neutral, from various food products 

 were used in place of the water in diluting 

 the 1 c.c. of extract to 5 c.c. Other ex- 

 periments were also simultaneously per- 

 formed, using the filtrates of food products 

 to which sodium fluoride had been added in 

 various quantities. Working in this way, 

 we have found that sodium fluoride when 

 present in milk in a concentration of 

 1:5,000 caused an inhibition of 89.5 per 

 cent. ; 1 :100,000 caused an inhibition of 

 87.8 per cent.; 1:1,000,000 caused an in- 



