350 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1954 



Was the picture faked and had the inscription been added to the nega- 

 tive for propaganda {purposes ? The perspective naturally altered the 

 shape of the house, and direct examination of the inscription told 

 nothing. It was therefore necessary to plot the inscription as it would 

 have appeared if it had been painted on a surface parallel to the photo- 

 graphic plate. This was done by geometric methods and it was then 

 found, in enlargements, that the letters were so arranged that no 

 painter could ever have done the work. The photograph was there- 

 fore faked, and there had been no such inscription on the building at 

 the time it was photographed. 



In certain exceptional cases, photographic conditions are such that 

 aerial photography has to be employed. This is particularly useful 

 in the case of large-scale disturbances on the public highway. 



Lastl)^ the development of motion pictures was bound to lead scien- 

 tific police investigators to try to adapt this technique to the recording 

 of particulars at the scene of the event. The first pictures of this type 

 were probably made in Brazil. While their usefulness may seem 

 questionable when it is simply a case of noting facts, they are undoubt- 

 edly a great help in the reconstruction of events where the investigator 

 is faced with several different possibilities. This system has not yet 

 come into general use, but there is no doubt that its advantages will 

 one day be acknowledged to outweigh its drawbacks, the most material 

 of which is the difficulty of showing a film in court. 



DEVELOPMENT OF METHODS OF SCIENTIFIC DETECTION— A FEW 



EXAMPLES 



It is impossible, in this article, to give a detailed account of the 

 present methods used in scientific detection. In any case, it is prefer- 

 able to show how they have developed and to indicate in a certain 

 number of cases, by actual examples, how they have been evolved and 

 how the pure and applied sciences have helped. 



First and foremost, we must emphasize the need for the forensic 

 scientist to adapt the methods of pure science to the particular aim 

 he has to achieve. Forensic science investigations, indeed, involve a 

 number of requirements, some of which are very exacting, regarding 

 the quantity of a substance to be analyzed, the time taken for the 

 analysis, or even the conditions in which the analysis itself is con- 

 ducted. These requirements must be observed and the methods of pure 

 science and technology, which have been developed to meet quite dif- 

 ferent purposes, must be adapted accordingly. 



One of the most typical examples of the application of the latest 

 scientific methods in the forensic field is that of the discovery of arsenic 

 administered with criminal intent. As we have already mentioned, 

 chemical methods developed during the second half of the nineteenth 



