1903] VEGETATION OF THE BAY OF FUNDY MARSHES 453 
Some of the phenomena of competition seem to imply that each 
plant is able to control by some chemical or other method still 
unknown, a certain sphere of influence about it, a limited area of 
space of which it is the center and from which it can exclude 
others, and that this sphere of influence, like other adaptive 
features of the plant, is modifiable adaptively. Gregarious 
forms would be such as grow together so closely that these 
spheres touch, excluding other forms, and before the advance of 
such a phalanx other forms of lesser vigor must all go down. 
Elsewhere these spheres, rigidly maintained against an enemy, 
might be relaxed to admit a friendly or cooperating form, and 
other of the phenomena commented upon in the preceding 
pages, might find an illuminating explanation in such a con- 
ception. But it is all pure speculation, and can be settled only 
by careful field experiment. Until this is given we shall not 
know whether associations are mere mixtures, or are to some 
extent cooperative communities, and if the latter, what the nature 
is of the bonds which unite their members. I have no question 
that ina properly equipped field laboratory, such as has already 
been mentioned, competent investigators, working with an 
experimental piece of ground, could solve this most vital of 
questions. Fortunate will he be who first has the proper oppor- 
tunity to attack it! 
NORTHAMPTON, Mass. 
BIBLIOGRAPHY. 
A. Local literature relating to the marshes. 
CHALMERS, R., Report on the surface geology of eastern New ee 
etc. Report of the Geological Survey of Canada, 1895, M, pp. 
CRAWLEY, H. O., Description of the method of reclaiming the ksh and 
adjoining marshes in New Brunswick, from the sea. Papers on Subjects 
connected with the Duties of the Corps of Royal Engineers 8: 194-195. 
18 
45. 
Dawson, J. W., On a modern submerged forest at Fort Lawrence, N.S. 
Quart. Jour. Geol. Soc. 2: 119-122. 1855. Also in Amer. Jour. Sci. II. 
21: 440-442, 
, Acadian Geology. First edition, London, 1855; also three later 
editions, 
Dawson, W. BELL, Survey of tides and currents in Canadian waters. Ottawa, 
Government Printing Bureau, 1899, pp. 36. 
