13 
Indeed, if any one will take the trouble to look at a good 
map of England, it will appear clear that there was hardly 
a spot so well calculated as a centre from which to inoculate 
our English rivers, as Rugby or the Watford Locks, near 
the Crick Railway Station. From such a point, situate at 
an altitude above the sea of about 350-feet, and very nearly 
at the line of watershed which divides England into the 
River Basins of the Severn on the west; the Trent on the 
“north; the Ouse on the east; and the Thames on the south; 
a few detached sprigs travelling different ways, would enter 
the Severn through the Avon via Rugby and Warwick; the 
Thames, through the Cherwell at Banbury, and thence by 
Oxford; the Nene, above Northampton ; the Ouse at Buck- 
ingham; the Welland, at Market Harborough; the Trent, 
above Burton, by the Anker and Tame; and again, lower 
down at Nottingham by the Soar; and from Nottingham 
the Witham could be reached by the Grantham canal, and 
from thence by Lincoln, the Drains of North Lincolnshire 
would be impregnated. And then, when the pest had tra- 
velled as far down (on the Trent, for example) as the top of 
the Humber), the numerous vessels ascending the Great 
Valley of 4,000 square miles, drained by the Yorkshire 
Ouse, would carry it up with them, and so inoculate that 
ample river and its numerous tributaries. 
That the plant is only now descending these rivers is evident, 
It has appeared in the upper part of the Ouse, and for four 
years has been observed in the Nene; two years ago it 
appeared at Lincoln, but had not then reached the northern 
parts of that country, and in our own river, while it occupies 
the line of descent from Cambridge to the sea, the * Old 
West” river and the “ Lark” are, as yet, free of it, except 
just above their confluences, Looking at these facts, I would 
ask, if it be a native, how is it that it has never exhibited 
its extraordinary powers of increase till now? For if it be 
