The Cold War was seen as a futile ground for the development and testing of many weapons and devices which were thought to ultimately improve American Combat Soldiers survival on the “Modern” battlefield. While some examples did, other were at best – strange. This brings us to the Model 40 Scent Identification Device or sometimes known as The “Sniffer”. It had been determined than Humans have a scent recognizable to each other. Theramones are an example. Often, other Humans may not detect such low level odors (as animals do). The US Military began to develop plans to create a Device capable of “smelling” another Human (especially one who may be well concealed on the battlefield. As was seen in The Vietnam War, Enemy Soldiers were quite adept at concealment. Often using underground Tunnel Complexes, they could “hide” out for extended periods.
The advent of the M40 Detection Device was supposed to correct that problem. In operation, a series of sensors (worn as a pack on the back of an Operator). Odors release through sweat and natural reactions to stress (fear), were picked up and would alert The Operator to an Enemy presence (via a series of tones hear through earphones). Once located (especially with hidden Tunnels), an Enemy could be properly engaged. The obvious drawbacks to The M40 were “false positives” brought about by both the presence of dead human bodies and decaying organic materials (plants – which was a facet of life in the Jungles of Vietnam). The cost of The Units and training required found that the need for another (cheaper form) of Scent Identification be developed. The M40 was quickly replaced by the tried and true use of Field Canines. Although just as quickly replaced The M40 would still be adopted into Government use for a myriad of related way to identify potential threats.