The work of an investigative dog.
As long as the work of a hunting dog is based on the direct hunting instinct, looking for human traces - only indirectly. The place of natural prey is taken by an artificial object - an object of retribution or a human being, from which the trace comes.
To train a dog to work on a human footprint or to identify the belonging of objects to certain people, terrains should be avoided at first, where the human trace crosses with the deceptive game trace. Later, during further training, the dog develops only the reflex of tracking human traces, and he quenches the hunting reflexes in this way, that with a stimulus, i.e.. with the trail of animals there is unpleasantness. However, too drastic measures must not be used, so as not to alienate the student from all the smells on the trail at all. Caution and far-reaching restraint in proceedings are all the more recommended, that in the case of olfactory work, the handler guides the dog in an area inaccessible to him, so it is very easy to misunderstand.
There is no doubt, that the dog can smell different species of animals, as well as their tracks. The question arises, whether he is also able to distinguish the smell of a particular individual among people and to identify the person. By identifying a person I mean, in a given case, the dog's ability to distinguish the crossing traces of several people and the ability to discern this person in a group of strangers., which belongs to a given trace or object.
Without going into theoretical considerations, can be judged from everyday life, that each person has his own personal fragrance, only proper to him. The individual smell of a person consists of the secretion of the sebaceous and sweat glands as well as the constantly flaking and decaying epidermis. The complex of these smells is characteristic of individual individuals and is different in each of them. Besides, each person's scent changes with age, and also depends on fatigue, mental illness or causes. A person sweats, e.g.. under the influence of pain or fear. These states do not depend on his will. Facial expressions can be mastered, without manifesting his spiritual experiences in this way, but a change in smell cannot be prevented. This explains the aggressiveness of dogs towards cowardly people, even if their behavior did not reveal their fears. Changing the smell undoubtedly also makes it easier for retrievers to find gunshots that do not even bleed blood, but probably emitting out of pain or mortal fear a smell other than healthy game fleeing or hiding from its pursuer. We must therefore take these differences into account when studying, selecting experimental objects as far as possible from different backgrounds and ages, so that the dog should not be overly challenged at first.
For a long time it was judged, that the dog, following the footsteps of a human, is guided solely by the smell of his body. Only Most's experiments proved that this theory was wrong and proved it, that the average dog is only guided by the smell of the trace.
Most's experience was more or less as follows: they walked across the meadow 2 people on lines crossing at right angles at some point. One of the people at the crossing point, going from south to north (dogs' owner), she turned east, continuing the way of the other person, which came to the intersection from the west 1 henceforth it continued northward, thus continuing the path started by the first person. Dogs not previously trained to identify traces were nearly all wrong. Starting my search for a trace of the lord from the southern beginning, they continued through the intersection in a straight line, so north, following in the footsteps of a deceptive stranger.
So it turns out, that an untrained dog does not follow the odor of man, but after the scent of the trail as such. On the basis of these trials, variously modified, research was undertaken on the smell of the trace.
The scent of the trace was named, rightly so, ,,bouquet of trace”. Different scents of flowers make up the fragrance of a bouquet, so the bouquet of the trace is composed of the various fragrances it contains. The most important of them are: individual man's fragrance, the smell of the footwear with its preservatives, the scent of vegetation being trampled on by the person laying the trail, and finally the scent of the earth oppressed by that person. This bouquet of scent affects the dog's sense of smell collectively, just like for a musically untrained ear, a chord of several tones extracted from the piano at the same time. However, be aware of this, that the individual components of the "bouquet" are of different intensity, so that some of them suppress others.
A classic example of a trace with an individual scent is the trace of a barefoot individual, spoconego, on the glass pane, thoroughly washed and free of any fragrances. Of course, we do not meet such traces in practice. Practice usually gives us traces of a number of people, walking on the same ground, among the same vegetation, sometimes in similar footwear, preserved with the same paste, differing only in their personal scent. The two bouquets in the examples mentioned thus have two identical components, one more or less similar, and only one different. No wonder then in this, when the dog cannot tell the two tracks from each other,for he has simply not learned to pay attention to the only determinant for trace identification yet, what is the individual scent of man.