126 THE NATURE -STUDY REVIEW [i, 3, may 1905 



had never seen or heard of, the children were led to reconstruct 

 a mental image of that creature, and to deduce various facts con- 

 nected 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 be- 

 longed, he brought it to school to be examined. The foot was 

 about as large as that of a small fowl, and was completely cov- 

 ered 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. (AL 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 thick- 

 ness 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 expe- 

 rience 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 knowl- 

 edge 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 hypoth- 

 esis. It was certainly, from its feet and plumage, not a water- 

 bird. *' Eliminating the impossible," as Holmes did, it did not 

 prey on other birds, nor get its food from beneath the ground. 



