378 



BOTANICAL GAZETTE 



[may 



six, and seven days respectively, tests were made with guaiac, alco- 

 holic aloin, and phenolphthalin. 



The tests with guaiac showed that the oxidase reaction which was 

 weak in the two- and three-day cultures was quite strong at four days. 

 The tests with alcoholic aloin and phenolphthalin showed that the 

 peroxidase reaction was strongest in the six- and four-day cultures, 

 and considerably weaker in each of the others. 



Certain phenomena observed in connection with the use of aloin 

 in aqueous and alcoholic solutions, suggested that they react differ- 

 ently with oxidases and peroxidases. Experiments were accordingly 

 installed to test specifically the action of each solution. Two solu- 

 tions of aloin were prepared: I, 0.250^ of aloin in 50" of water. 

 II, o.25o« m of aloin in 50" of 95 per cent, alcohol. One cubic 

 centimeter of aloin solution I or II was added to 5 CC of liquid in test 

 tubes, according to the plan shown in Table VIII. The tubes were 

 prepared and aloin added at 2 .45 p. m., on January 10, and the obser- 

 vations recorded in the third column of the table were made at n A. ft 



J 



The culture liquid when added to the tubes showed 



no oxidase but good peroxidase reaction with guaiac. 



TABLE VIII 



Comparative reaction of aqueous and alcoholic solutions of aloin to a iq 



containing peroxidase. 



Nos. 



1 and 2 



3 an <* 4 

 5 and 6 



7 and 8 



9 and 10 



11 and 12 



Solution 



<< 



Unboiled liquid + icc aqueous aloin 



Boiled " + 



Distilled water + 

 Unboiled liquid + 

 Boiled " + 



Distilled water + 



alcoholic 



<i 



Color observed 

 1 1 A. m., January n 



yellow 



An inspection of these results shows that when only P^ *^ 

 present, aqueous aloin is not particularly applicable for del * 101 ^ ^ 

 the presence of that enzyme in the absence of growing plan 



the boiled as m 

 changed to 



there was the same development of pink color in 



unboiled liquid. Alcoholic aloin, on the contrary, was ""TJ^ in 



deep pink in the unboiled liquid, but remained unchange 



s next tested in Wf* 



the boiled liquid and in the distilled water. 



ids 



The action of the different aloin solutions was 



