To further purify the oil, I next boiled off some of the water. I didn't want to boil too much of it though, and risk losing any oil I had been able to collect. It is unlikely that I will try to purify it any further. Not only would it be very difficult to do so, but I would probably have to repeat the whole process again with more leaves to get enough oil for my purposes, and there is not much time left in the school year. However, I believe it is alright if the wintergreen oil is not pure.
Next, I plan on preparing two or three Petri dishes of bacteria. Over the next few days, I want to apply the oil I distilled to one dish and leave the other as a control, and monitor the growth of the bacteria to see if the oil is actually toxic. If I can get a hold of some pure methyl salicylate, which is the primary chemical in wintergreen oil, then I will apply that to the third dish as another point of comparison. I am very interested to see the results of all this, and I am excited to share them with the class.