The epoxy resins, especially Spurr's epoxy resin, are time consuming to prepare and dangerous to work with. In an effort to minimize contact time with the resin and to conserve components, we prepare one large batch of resin (minus catalyst) that is then dispensed into glass scintillation vials that are tagged to give the exact weight of resin in the vial, The resins are stored in the freezer (preferably -70° C) until needed at which time they are thawed and the appropriate amount of catalyst added. After mixing by gentle inversions and stirring, the resins are dispensed as needed using widebore pipettes. .Any resin remaining in the vial may be refrozen several times after adding a puff of Freon or dry air to the via!. When the resin becomes too depleted or too old to refreeze, the vial is placed into a 60° C oven and the contents polymerized. The vial may then bs discarded or recycled (i.e., reused) untii the space in the vial is diminished to an unacceptable level.

This article is the first in a series relating to the application of microscopy to forensic science. As such, the article is intended to be purely introductory in nature. Future articles will be specific both as to the forensic challenge and the solution as allowed by the creative application of microscopy.

Microscopy has played an integral part in forensic science since the early part of this century. In 1928, E. Locard established the practical and theoretical underpinnings of the microscopic examination of trace amounts of evidence. The “exchange principle of evidence” was so developed:

Whenever two objects come into contact there is always a transfer of material. The methods of detection may not be sensitive enough to demonstrate this or the decay rate may be so rapid that all evidence of transfer has vanished after a given time. Nonetheless, the transfer has taken place.