I expect Poole has told you that I have searched London for the chemicals I need. It is no good. I have decided that the first chemicals I bought were not absolutely pure. By accident, they contained something unknown to myself or to the chemist that prepared them. And that unknown something made my drug effective. So my drug was an accidental discovery that cannot be repeated.
我想普尔已经告诉你我找药找遍了伦敦，但却毫无结果，我这才明白第一批货是不纯的，正是我和药剂师都还不认识的那种杂质使我的药成功了。这么说来，我配的药便是偶然的发现，不可能重复的。

About a week has passed. I have used the last of the old chemicals, and for the moment I am Henry Jekyll again. But Icannot write much more—I have very little time. If Hyde returns while I am writing this confession, he will tear it to pieces to annoy me. If I finish it, however, he will probably not notice it.
一个星期过去了，我用完了最后一点第一批买的药，这会儿我又是亨利·杰基尔了。但我写不了多少东西了，时间不够了。如果写这些忏悔时又变成海德，他会把这些纸撕成碎片来气我的。但如果我写完了，他也许不会注意到的。