I was doing some research this morning, and ran across an excerpt from the government's brief filed on Dec. 29, 1979, which seemed to me to be particularly germane to some of the things that have been going on recently in the MacDonald case:
From pages 135-136 of
http://www.crimearchives.net/1979_macdonald/court/1979/1979-12-29_4thCircuit_EDNC_gov_brief.html
"Scientific evidence is admissible only if the principle upon which the evidence is based is 'sufficiently established to have gained general acceptance in the particular field to which it belongs.'
Frye v. United States, 54 App. D.C. 46, 293 F. 1013, 1014 (1923);
United States v. Baller...However neither absolute certainty of result nor unanimity of scientific opinion are required for admissibility. For example, in
United States v. Cyphers, 553 F.2d 1064 (7th Cir. 1977)
cert. denied, 434 U.S. 843 (1978), an expert's opinion that human hairs found on items used in the robbery 'could have come' from the defendant was entitled to be admitted for whatever value the jury might give it. The Court explained that where a witness, properly qualified as an expert, bases his opinion on what he believes to be a reasonable scientific inference, his opinion should ordinarily be admitted subject to cross-examination concerning the propriety of the testing techniques used and the validity of conclusions drawn from his observations. In addition, the newness of a scientific technique does not alone render its results inadmissible, since 'every useful development must have its first day in Court.'
United States v. Daller, supra, at 438;
United States v. Brown, 557, F.2d 541 (6th Cir. 1977)."