California Association of Criminalists
Since 1954
MICROCHEMICAL IDENTIFICATION TESTS FOR THE DANGEROUS DRUGS: AMPHETAMINE, BARBITURATES, NARCOTICS, ETC., WITH EMPHASIS
ON ALTERED FORMS AND INTERFERENCE
George W. Lacey, Los Angeles County Sheriff's Department
It was decided that the ultraviolet spectrophotometric approach is the most practical for those laboratories having this instrument. It was decided that infrared spectrophotometry and X-ray diffraction analysis are of application in certain cases. The classical methods of melting point, characteristic microscopical crystals, and specific spot tests, although of some use, are less reliable and less sensitive than the instrumental methods.
THE VALUE OF THE ACID PHOSPHATASE TEST FOR SEMINAL STAINS
Jack W. Cadman, Orange County Sheriff's Office, Santa Ana, CA
It was decided by the group that the acid phosphatase activity test has acceptable validity in criminalistic work for stains of seminal origin. It was pointed out that positive tests have been obtained on five-year-old known seminal stains. Sources of contamination were discussed, and it was felt that further investigation into various possibilities is indicated, especially sources from contraceptives and vaginal stains.
PROBLEMS IN THE FIELD OF TYPEWRITING IDENTIFICATION
Ray H. Pinker, Crime Investigation Laboratory, Los Angeles Police Department
The use of gauges in connection with typewriting identification was discussed. It was pointed out that off-vertical alignment and off-anvil characteristics are the most significant features in the individualization of a new machine when damaged letters are not present.
RECOVERY OF VOLATILE FLAMMABLES IN CASES OF SUSPECTED ARSON BY VACUUM DISTILLATION
Ralph F. Turner, Department of Police Administration, Michigan State College
RECOVERY OF VOLATILE FLAMMABLES IN CASES OF SUSPECTED ARSON BY STEAM DISTILLATION
James W. Brackett, Jr., Laboratory of Criminalistics, Office of District Attorney, Santa Clara County, CA
Vacuum distillation apparatus and processes in the recovery of flammables were discussed with comments on time of distillation, percentage recovery, sample size, and identification of recovered fractions. Steam distillation procedures were discussed in respect to the same points, and it was pointed out that by use of elevated boiling point modifications there is a superiority in performance of the steam distillation procedure over the vacuum distillation procedure in respect to: (1) Quick recovery; (2) Maintaining identity of original sample; (3) Cost of apparatus; and (4) Physical space of apparatus.
DISCUSSION OF ODD AND UNUSUAL CONTAMINANTS OF FOOD AND DRINK
Don M. Harding, Pasadena Police Department
The general problems confronting criminalists in connection with the examination of food and drink materials were discussed with each member present indicating some of the novel incidents in his experience. A systematic analysis procedure for such problems was then detailed.
SKELETAL IDENTIFICATION
Don M. Harding, Pasadena Police Department
General aspects of this subject were discussed and various sources of technical assistance pointed out. The role of the physical anthropologist, importance of related physical evidence, importance of dental evidence, and the use of photo-overlays (skull over portrait) were gone into in some detail.
DERMAL NITRATE TEST
This subject came up spontaneously and was discussed with a great deal of enthusiasm. It was unanimously agreed that the paraffin-diphenylamine test for dermal nitrate residues from revolvers should be discontinued as a criminalistic procedure. It was agreed that the examination of the hands microscopically for powder-burn residues has merit as a proper procedure for the detection of residues resulting from firing a revolver. Negative findings, nevertheless, are inconclusive.
