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consequent deficiency of food is a more plausible theory, 
but I have always noticed that, just as with the swallow, 
a few individuals have preceded the main body, and that 
during the first autumn the numbers are never large, but after 
a winter spent beneath the snow they begin to breed with the 
first days of summer, and thus develop the extraordinary 
multitude which is, as it well may be, the astonishment and 
terror of the country. It appears, then, that excessive reproduc- 
tion is rather the result than the cause of migration. It has 
also been suggested that the course taken by the lemmings 
follows the natural declivities of the country, but a reference to 
the maps will show that in that case nearly all the Norwegian 
migrations should take a southerly route, which is by no means 
the case. On the contrary, westward at Heimdal means across a 
rapid river, over a wide lake, and up a steep, rocky and snowy 
mountain, and this is the course which is followed. Now, this 
ends eventually in the ocean, and thus we are again landed at the 
question from which we set out. After all, it is not the power 
of direction which is so remarkable : this is a faculty possessed 
by many animals, and by man himself in a savage state. A 
young dog which I took from England, and then from my home 
in Yaage by a path to Heimdalen, a distance of 46 miles, ran 
back the next morning by a direct route of his own, crossing 
three rapid rivers and much snow, and accomplishing the 
distance in six hours, without the vestige of a path. This same 
dog afterwards repeated the feat, but followed the path, and 
took two days in reaching his destination, hindered and not 
aided, as I believe, by his experience. Herr Palmen, indeed, 
says “ experience guides migration, and the older migrants 
guide the younger,” like one of Mr. Cook’s personally conducted 
tours. This obviously cannot be the case with the lemmings. 
It is now generally admitted that instinct is merely inherited 
experience, and is therefore primarily calculated to benefit the 
species, unless indeed circumstances have changed meanwhile 
more rapidly than the structures to which the phenomena of 
instinct are due. Now, the lemmings during their wanderings 
pass through a land of milk and honey, where, if their instincts 
could be appeased, they might well take up a permanent abode, 
and yet they pass on, whilst their congener, the field-vole, 
remains in quiet possession of the quarters from which he was 
temporarily ousted. It is indeed almost as strange a sight to 
see the holes, the deeply-grooved runs, and the heaps of refuse 
of these restless creatures, which have passed away but yesterday, 
as it is to see the fjelds suddenly become alive with a new and 
boisterous tenant, who, like another Ishmael, has the hand of all 
men against him. 
Now, if we compare the migration of the lemmings with that 
