How have courts interpreted the possession of a class A drug?

Graham v. United States, (6 Cir. 1958) 257 F.2d 724 is not in point. There the prosecutor argued an erroneous principle of law, "that once the Government proved that the defendant had narcotic drugs in his possession, then the defendant had to prove that he got it from a doctor or a druggist. This was not a correct construction of the statute or of the issue in the case. * * * Possession by appellant under circumstances claimed by him to exist in this case, was, if believed by the jury, also a valid defense to the charge." pages 729-730.