294 
NATURE 
[Fuly 30, 1885 
The relative dexterity of the legs was tested in a number of 
cases, but a press of other duties prevented further experiments 
in this direction. From the tests made, however, it is obvious 
that there is no direct relation of the relative dexterity of the 
legs to the bias in walking. 
From these experiments it is evident that the cause of the 
observed unconscious bias in walking is not to be found in the 
mechanical proportions, or relative strength, or dexterity (?) of 
the legs. 
The application of well-established physiological principles 
will, however, furnish a ready explanation of the phenomena in 
question. 
The co-ordination of the voluntary muscles is the exclusive 
prerogative of the nervous system and the senses are important 
factors in all movements involving a definite direction, The 
muscles of locomotion when called into action under ordinary 
conditions, as when walking in a straight line, are co-ordinated 
or brought into an orderly correlation, by impulses conveyed to 
the nervous centres through the afferent or sensory nerves, but 
when in the dark, or ina mist, or when one is blindfolded, the 
senses are not available as a guide to direction, the co-ordinating 
nervous mechanism is dormant, and a divergence from a right 
line is made to the right, or the left, from a lack of equilibrium 
in the action of the efferent or motor nerves. 
In several of the trials, to determine the bias in walking, inter- 
ruptions occurred before the course was completed, by the open- 
ing of the door at the side of the hall and the talking, in a low 
tone, of the visitors, which served as a guide in orientation, and 
the curve made before the interruption was suddenly corrected 
to a line parallel to the meridian. 
In all of the trials the greatest care was taken to prevent the 
senses from gaining clues to the right direction. 
Unconscious bias in walking is obviously the result of vital 
activities involving complex actions and reactions in the nervous 
system, which may be clearly defined in general terms, while the 
details of the obscure changes taking place in the nervous 
mechanism cannot, in the present state of our knowledge, be fully 
traced. Moreover, it is evident that the phenomena in question 
must be studied from the same stand-point of other biological 
processes which cannot be explained or expressed by purely 
physical or chemical conditions. MANLY MILES 
Massachusetts Agricultural College, Amherst, 
Mass., April 7 
The Flora of Canada 
THE review by Mr. J. G. Baker in your last number (p. 242) of the 
second part of Prof. Macoun’s ‘‘ Catalogue of Canadian Plants ” 
prompts me to send you a few notes on some of the features of 
the flora of Canada, which I had an unusual opportunity of ob- 
serving last autumn under the guidance of Prof. Macoun in the 
neighbourhood of Ottawa, and again in the magnificent railway 
trip given to members of the British Association by the Canadian 
Pacific Railway Company from Lake Superior to Kicking-Horse 
Pass in the Rocky Mountains. 
Throughout Eastern Canada and the Eastern United States 
the European botanist is struck with the strange intermingling, 
in the wayside flora, of forms new and strange with those 
familiar by every roadside and in every hedge-bank in England. 
Away from human habitations the flora is almost altogether 
novel, but near houses, introduced purposely or accidentally, 
the English weeds are rivalling and even supplanting the native. 
I was particularly struck with noticing the vegetation of the 
grass lawn by the hotel on the Catskill Mountains at an eleva- 
tion of about 3000 feet. It consisted almost entirely of the same 
species as you would expect to find in similar situations at a 
lower altitude in the old country: Achillea Millefolium, Daucus 
Carota, Plantago major, Chenopodium album, Cnicus lanceolatus, 
&c,, most or all of them importations. Elsewhere, in the east, 
you find docks, milfoil, thistles, shepherd’s purse, jostling 
Asters, Asclepiases, Amaranthuses, Solidagos, and other peculiarly 
American weeds. Exactly the same thing is taking place with 
introduced animals. I was staying at a farmhouse in Ontario, 
not far from Niagara, and was told that the English house- 
sparrow made his appearance there about three years since, and 
is already as abundant as in England, and a terrible nuisance. Some 
English plants, however, like our daisy and primrose, seem to 
refuse to naturalise themselves to the American soil and 
climate. 
Everywhere the lines of the railways are marked by the advent 
of the foreigner. As Prof. Asa Gray said at Montreal, even 
English weeds now travel by express train. It is most inter- 
esting, in travelling westwards over the vast continent, to note 
the gradual disappearance of European and the unrivalled 
supremacy of American types. But it isnot only westwards that 
the tide of floral conquest makes its way. A fellow-traveller of 
our party had the good fortune to gather, near Port Arthur on 
Lake Superior, where we were detained twenty-four hours by 
stress of weather, a grass, Beckmannia eruceformis, 300 miles 
east of any locality previously recorded. 
Although in the main the indigenous American flora is alto- 
gether different specifically from ours, yet there are exceptions. 
I am not now speaking of the Alpine flora of the Rocky Moun- 
tains, which agrees to a wonderful extent generically, and even 
specifically, with the flora of the Alps, Pyrenees, or Grampians. 
Covering the vast extent of ground from the eastern sea-board 
to the Rockies are a few species undoubtedly indigenous and 
absolutely identical with European and even English forms. I 
may mention three illustrations taken from widely-separated 
natural orders—Polentilla fruticosa, Campanula rotundifolia, 
and Linaria vulgaris. Wow to reconcile these facts with any 
theory accounting for the geographical distribution of species on 
the face of the earth it is difficult to say, 
Even more interesting are those cases where American and 
European plants are regarded as belonging to the same species, 
but where there is a certain difference difficult to define, but 
recognisable at a glance. To take, again, three eximples :— 
Among the most cosmopolitan of ferns are Osmunda regalis and 
Pteris aguilina. Abundant throughout Canada, there is yet, 
in both cases, a general habit by which they are at once dis- 
tinguished from the English forms. Again, the American 
Plantazo major is all but indistinguishable from the English 
wayside weed. And yet, it is said, American horses know the 
difference. Prof. Macoun is contemplating a visit to Europe 
next year, when one of his special objects will be to compile an 
account of these closely-allied but yet distinct eastern and 
western forms. It is possible that such a comparative list—and 
it could not be in better hands—may throw some light on some 
of the many still unsolved problems connected with the evolu- 
tion and distribution of species. ALFRED W. BENNETT 
The Fauna of the Seashore 
In addition to the instances from the Molluscan class men- 
tioned in the interesting letter from Mr. Arthur R. Hunt 
(NATURE, pp. 243-4), as illustrating—after Prof. Moseley’s 
most valuable contribution—‘‘the variety of method exhibited 
by the littoral fauna in resisting wave-currents,” may be men- 
tioned one of a higher class among the fishes—viz., the common 
smooth blenny (Blennius pholis). 
No one who has hunted for this pretty little fish in rock-pools, 
or who has kept it in an aquarium, can have failed to notice its 
remarkable adaptation to the ever-varying environment of the 
littoral zone. The angular form of the head and smooth, 
mucous-covered body enable it readily to burrow within the 
smallest crevices of the rocks, to prevent its being washed ashore 
when the tide is coming in, and to prevent its being carried into 
deep water when the tide is going out, where it would readily 
fall a prey to rapacious fishes, as it has apparently little power 
to swim freely to a distance, not needing to do so in shallow 
water. Its peculiarly modified ventral fins, forming almost 
anterior limbs, enable it to cling securely not only to weeds and 
rocks, but even to perpendicular surfaces, for similar purposes to 
those above stated, while its beautifully-marked body—of 
splashed dark and light greens—seems to be a case of mimicry 
of the sea-weeds which afford it protection from its natural ene- 
mies among its own class and those of the higher Crustacea. 
An allied deep-sea genus (Avharricas, the wolf-fish), whose 
ancestor was probably a littoral blenny, has the ventral fins 
entirely wanting, and the head is round, for the obvious reasons 
that it does not need to cling to surfaces nor to burrow in 
crevices. This fish is, however, compensated by a formidable 
array of sharp teeth to protect it from its natural enemies. In 
the aquarium no fish, in my experience, is so readily tamed as 
the smooth blenny, so as to allow it to be handled, or exhibits 
such a high degree of piscine intelligence, arising doubtless from 
long education, both inherited and acquired ; in the varying 
environment which is its habitat. A specimen now in my 
aquarium daily avails itself of the advantage of the dry ledge of 
the slope-backed tank ‘‘to get a mouthful of fresh air,” while 
