Interconvertible Naturally Occurring Auxins 41 



Dr. Fawcett: I'd just like to say that from some advice that Dr. 

 Bennet-Clark gave a year or two ago we switched from using ether to 

 ethyl acetate for the extraction of indole compounds. Although we 

 ran into some problems with emulsions, we found that we got a much 

 better and wider spectrum of the indole compounds. I wonder if Dr. 

 Bentley had any experience in using ethyl acetate with the algae. 



Dr. Bentley: No, I haven't used ethyl acetate and I couldn't say 

 anything about it really. 



Dr. Nitsch: May I ask Dr. Bentley a point of technique which is 

 very important? Could you tell me if you leave the solvent in the 

 tank and use it over and over again? 



Dr. Bentley: No, we mostly renew it. We found that the percent- 

 age of ammonia changes. 



Dr. Nitsch: Do you use fresh solvent every time? 



Dr. Bentley: No, not necessarily every time. 



