SCIENTIFIC DETECTION OF CRIME — S ANNIE 341 



of the nineteenth century and developed side by side with the chemical 

 sciences. As a poisoning cannot be discovered unless the chemical sub- 

 stance employed by the criminal is identified, the only way of bringing 

 the crime to light is to make a chemical analysis of the substance con- 

 cerned. One of the earliest examples of the importance of chemical 

 methods in criminal proceedings was the famous controversy which 

 brought Orfila into conflict with his colleagues in the Lafarge case 

 (1840) ; this controversy would never have arisen had the chemical 

 methods used during the proceedings not been so ineffectual. Even in 

 our own time, is it not true that disputes still arise between toxicolo- 

 gists, and are nearly always due to the imperfection of the scientific 

 techniques employed? This goes to show how greatly the improve- 

 ment of a scientific method in this field can further the cause of justice. 

 Up to 1880, the chemical crime, i. e., poisoning, was the only form 

 of crime to which truly scientific methods were applied. Apart from 

 the evidence supplied by the medical expert, the investigator relied 

 solely on evidence given by human witnesses. Bertillon was the first 

 to introduce factual evidence systematically into the detection of crime. 

 At that time, and almost simultaneously in all European and Ameri- 

 can countries, it was at last realized that every criminal leaves behind 

 him some tangible evidence of his crime, which, if correctly interpreted, 

 may, independently of all human testimony, supply proof or circum- 

 stantial evidence of immense value. Such was the origin of scientific 

 criminal investigation, i. e., forensic science, which has made steady 

 progress during the past 50 years ; there is a growing tendency to sub- 

 stitute it for verbal evidence or, at least, to have it reinforce the latter 

 as effectively as possible. 



SCIENTIFIC DETECTION OF FALSEHOODS 



It was inevitable that the progress of scientific methods in the field 

 of factual evidence should have repercussions on evidence given by 

 human witnesses. As early as 1892, Ferri had advocated, in his Crim- 

 inal Sociology, the use of hypnosis to "try out the reins and the heart" 

 of a criminal and reveal his innermost thoughts. Lombroso used a 

 sphygmograph to register a suspect's emotional reactions. Research 

 on the possibility of detecting lies by testing a suspect's pulse, Ijlood 

 pressure, respiration, psychogalvanic reflex or electric reactions of the 

 skin, etc., was carried out by Muensterberg in 1904, Marston in 1915, 

 Larson and Vollmer in 1921, and Father Summers in 1932. 



In the application of scientific methods to the interrogation of hu- 

 man witnesses, two very different lines have been followed. Under 

 the first system, the aim is to suppress the consciousness of the individ- 

 ual being questioned, so that his subconscious may be freely explored. 

 Although all methods based on hypnosis have failed, those involving 



