3'2-4 A s o , Oll the Nature of Oxidases. 



a streng Griess reaction as woll as the iodine reaction very de- 

 c'idedly. biit not tlie giiaiac reaction wliile the aqueous Solution 

 of the well-washed precipitate gave in the contrary not the 

 Irriess reaction nor the iodine reaction, bnt a strong guaiac re- 

 action. This result proved positively that the substance 

 which gives the guaiac reaction is not the same that 

 liberates iodine from potassium-iodid. 



Bach and Chodat^i have mentioned that when a freshly 

 cut surface of Sagittaria bulb witli paper moistened with po- 

 tassium-iodid-starch, is touched a bhiish violet ring will apj^ear 

 along the peripheral tissue after a short tinie, further a blue 

 ring with a paper moistened with guaiac tincture, and fui'ther 

 with m-phenylendiamine, along the same lines. I have repeated 

 these experiments and made a similar Observation. Hence I took 

 off the peripheral part of twenty one bulbs and crushed it with 

 30 c. c. water. The pressed juice gave a strong guaiac reaction 

 and a moderate Griess reaction, but the iodine reaction only 

 slightly. To 30 c. c. of the juice about 100 c. c. absolute alco- 

 liol were added and the alcoholic filtrate was evaporated to 

 dryness. The residue was dissolved iu 10 c. c. water and tested 

 with the following result: 



Guaiac reaction 



No reaction at all 



Griess' reaction 



moderately 



Jodine reaction 



slightly. 



Iu tlie case of a feeble iodine reaction, tlie addition of a drop of 

 dilute sulphui'ic acid is preferable to accelerate tlie reaction. 



The aqueous Solution of the precipitate produced a very 

 strong guaiac reaction, but no Griess nor iodine reaction. Mo- 

 reover, I carried out several tests with the juice of skinned 

 bulbs according to Bach and Chodats method, but neither 

 Griess nor iodine reaction* was obtained while the guaiac reaction 

 appeared very strong. Also, on application of guaiac tincture 

 on the scratched surface of the freshly cut bulbs the blue color 

 appeared at once, while there was no reaction obtained with 

 potassium-iodid-starch. This result convinced me that the bulb 

 of Sagittaria (excluding the skin) contain common oxidase, but 

 no nitrite. 



•40 grams of Potato buds (2 — 5 cm long) were crushed and 

 the juice was pressed out. This juice did neither yield the po- 

 tassium-iodid-starch reaction nor the Griess reaction, which ho- 

 wever appeared very weak after purification. About 5 c. c. of 

 the juice was mixed with some concentrated Solution of basic 

 leacl acetate and filtered. The filtrate was mixed with sulphuric 

 acid and sulphanilic acid, then with «-naphthylamine liydro- 



1} Berichte der D. Chein. Ges. XXXVll. 1904. Heft 1. p. 39. 



