The Methods of Sherlock Holmes in Nature-Study by E.A. Greening Lamborn 1905
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Sir Arthur Conan Doyle’s famous detective was able from an examination of an old bowler hat to give an account of the appearance, occupation, habits, character, and worldly circumstances of its owner. Similarly, from an inspection of his friend's watch, he was enabled to discover that its former owner was a man of fallen estate and character, a drunkard, spendthrift, etc., a physical, wreck, and a victim of chronic poverty. Many other instances will occur to the reader in which Holmes was able, by the exercise of his sense organs and his reasoning faculties on some concrete object, to construct a whole chain of facts with which that object was connected.
In the explanation of the methods by which he arrived at these results, it will be seen that the faculties upon which he depended for his conclusions were :—
I. Observation, by which he obtained the external facts connected with the object. In the case of the hat above quoted, he observed the size, shape, condition, kind of lining, newly-cut grizzled hairs, smell of lime-cream, tallow stains, etc.
2. Deduction, by which he gained new facts as inferences from the ones already obtained. From the large size he deduced a large brain and consequent intellectual power, from the quality of the hat the well-to-do state of its purchaser, and from its interior stains his physical condition, among other inferences.
3. Memory, by which he was able to associate his newly-discovered facts with those in his past experience. For example, his memory informed him that the particular shape he had observed was in fashion three years before, so fixing the time of the hat’s purchase.
4. Constructive imagination, by which he was able to combine his facts and build them into a homogeneous hypothesis—that the person he wished to discover was Henry Baker, a man formerly well-to-do, fallen on evil days, of sedentary habit, in poor domestic circumstances, etc. The story, of course, is that of “The Blue Carbuncle.”
In his wonderful power of obtaining facts from the examination of concrete things the great detective of fiction is an ideal type of the nature-student. Though his observations of nature were limited mainly to man, and especially to criminal man, yet the faculties and the methods he employed are equally applicable to all natural objects; and if objection be made that Sherlock Holmes never existed, even without the knowledge that he is the creation of a man of science and had a prototype in fact in Dr. Bell of Edinburgh, it may be remembered that the great “nature-student” Cuvier, by the exercise of precisely the same faculties as those previously analyzed, was able, from an examination of a single bone, to reconstruct in imagination the animal of which it formed a part. This illustration in actual fact is at least as wonderful as any of the detective’s logical achievements in fiction. The faculties used by Sherlock Holmes and Cuvier are simply those possessed but not used by the average child in the elementary school. This is the great attraction of Sherlock Holmes. When he explains his course of reasoning to his astonished clients, they realize that all that he saw they might have seen also, and that the faculties which seemed supernatural were really the ordinary ones which they shared in common with him, but which in his case were used, in theirs were neglected. It should be noted, however, as Holmes repeatedly points out in his “explanations,” that people fail, not to see things, but to reason from what they see. They do not “proceed to draw inferences from their observations.” For instance, millions of people before Sir Isaac Newton had seen an apple fall from a tree, but no one until his day had ever gone further and reasoned why it fell. This has an important bearing on nature-study in schools, as it proves that, somewhat contrary to the common idea, it is in deductive power rather than in observation that training is required.
To illustrate the application of the foregoing to nature-study in the elementary school, the writer proposed to describe the progress of an “investigation” which took place in his own school. By the exercise of their faculties of observation, deduction, memory, and imagination on the foot of a creature they had never seen or heard of, the children were led to reconstruct a mental image of that creature, and to deduce various facts connected with its habits and surroundings. (The sceptical are invited to find the faulty link in the following chain of argument before talking of “impossibilities.”)
A “newly-severed” foot was discovered by a boy on a local dust-heap, and not knowing to what manner of creature it belonged, he brought it to school to be examined. The foot was about as large as that of a small fowl, and was completely covered with thick white fur or feathers. This much was obvious from a superficial observation. Closer observation disclosed four toes beneath the covering which was seen to consist of hair-like feathers. Memory thus assisted to furnish the first deduction, that it was the foot of a bird. (N. B.—This, as will be seen in the sequel, was not immediately obvious, as the foot superficially rather resembled that of a large white rabbit.) The deduction from the size of the foot was that the bird was rather larger than a partridge but smaller than a fowl. From the color and thickness of the feathers on the foot the inference was that the bird would be warmly covered with thick, downy feathers in which white was the prevailing color. But the children’s previous experience had told them that, by a recognized law of nature, the structure of any creature depends upon its surroundings. The bird in question must therefore have its home in a cold climate amid a snowy environment. It was therefore not an English bird, but probably came from the north. Geographical knowledge fixed its probable habitat as Northern Scotland, Norway, Sweden, or Russia. Further, the children knew, from a previous lesson on the stoat, that most wild creatures whose prevailing color is white change their color with the season and darken as the snow melts. The color of the bird in question might be therefore expected to vary with the seasons.
Observation of the toes showed the claws to be small and weak. The owner was evidently not a bird of prey. It was not a swift runner either. Neither could it scratch the earth in search of food. Could it, like many weak-toed birds, be insectivorous? The previous deduction of a cold climate negatived this hypothesis. It was certainly, from its feet and plumage, not a waterbird. “Eliminating the impossible,” as Holmes did, it did not prey on other birds, nor get its food from beneath the ground, nor from the air nor the water. Therefore it must live on plants which grew above the ground. But its weak, muffled foot showed that it could not perch in trees to feed on fruit or berries (the rigorous climate, again, was against the presence of trees). Such a bird looked like starving until it was suggested that it fed on leaves and shoots of plants. This again corroborated the early inference of a harsh climate, as these would be almost the only food available. (Some of the children had read about the reindeer and its food.)
Again, the clumsy foot was much against the possibility of the construction of any nest. A bird with such a foot would most likely lay its eggs on the bare ground. In accordance with a law previously quoted, the eggs would probably be of a brown tint, mottled to resemble the earth. The number of eggs would tend to be large, first because “ground-game” are especially assailable by enemies and seldom rear the full brood, and also because, however many eggs are laid on the ground, there is no danger, as in trees, of any falling out of the nest.
Summing up the facts thus deduced from the foot, the children were invited to imagine, as its owner, a bird as large as a small hen, covered with thick white feathers even to its toes, inhabiting the countries round the Arctic Sea, feeding on lichens, leaves and young shoots of plants, and laying a large number of brownish eggs on the bare ground. Obviously the next thing was to discover whether such a bird existed in fact, and if so, what it was called.
Sherlock Holmes having evolved such a description of an unknown individual, would have discovered the person answering to it by making inquiries in the locality in which he thought he might be found. As it was plainly impossible in this case to inquire in Northern Europe, a natural-history book was procured, and the plates in it were examined to see if any one of them tallied with the mental image gained by the children. Practically all the children recognized at once a plate which was stated to be a picture of the ptarmigan. The appended description was then read by one of the boys, and it was seen that practically all the deductions were correct, and that also the printed account only supplemented the deduced one in some minor particulars. This the reader may see for himself by reference to any book on birds.
It is not, of course, suggested that children could possibly arrive at such a result unguided, but it is in good faith asserted that all the deductions above stated were elicited from a class of older scholars who had never seen more of the bird in question than the foot they had before them. Such an object lesson as the one described is doubtless very uncommon, and opportunities for a similar prolonged course of reasoning would rarely occur in school work; but the writer’s aim in describing it is to show the possibility of applying in school work those methods and faculties which Sherlock Holmes in fiction and Cuvier in fact used with such striking results. It seemed an exceptionally good illustration of the way in which the various faculties should cooperate and their results be coordinated in the “scientific” examination of a natural object. But in every nature-lesson examples will occur of the way in which a single observation may furnish several deductions, which may again be associated with facts already in the memory to enable the imagination to build up a hypothesis. [From Indian Journal of Education, Madras, January, 1905.]