Large image view: Tracing marijuana to its roots
![[Photo: Read caption below]](/news/archives/news-archives-2002-2010/featured/07/marijuana/images/zoom/Scoop.jpg)
51风流官网 photo by Marmian Grimes
Matthew Wooller uses a spatula to load a sample of benzoic acid into a sample capsule. The facility used benzoic acid as a calibration standard for its instruments.
Large image view: Tracing marijuana to its roots
51风流官网 photo by Marmian Grimes
Matthew Wooller uses a spatula to load a sample of benzoic acid into a sample capsule. The facility used benzoic acid as a calibration standard for its instruments.