16 
The methods for suppressing the growth of Ulva may be grouped 
under three heads. An obvious and effective method in certain 
localities is to reclaim the land. This, however, is not always 
practicable. Two other courses are open, namely :—to poison the 
plant by the application of chemical substances ; or, to hold its 
growth in check by the regulation of local conditions based on a 
knowledge of its ecology. The chemical treatment even when easy 
of application requires to be exercised with caution on account of 
the danger to fish. It is a subject receiving attention from chemists 
and need not be further alluded to here. The last of the three 
methods opens up a very large and interesting field of enquiry, and 
one which will also probably yield results of considerable service in 
the solution of the Ulva difficulty. 
he magnitude of the nuisance appears to warrant a thorough 
study of Ulva latissima. This should embrace not only cultures im 
the laboratory and in the open with regard to its nutrition, but an 
investigation of its natural growth along an extended area of the 
) 
paid to the effect of currents. The season was somewhat late for 
the purpose but interesting data were obtained, 
Two rivers flow into Southampton Water. The Test at the 
north-west corner which passes through some small towns and 
villages ; the Itchen on the east side into which practically all the 
sewage-effluent of Southampton and Eastleigh is discharged, and 
which therefore may be regarded as being badly polluted. The 
peculiar double tides in the locality probably do not aid the escape 
of the river water, Near the town of Southampton there are at 
times considerable accumulations of Ulva, which in warm weather 
putrefy and emit offensive smells. The statement by one of the 
residents, that the white paint of boats is blackened in a night, is im 
accord with observations in other places and shows that the air 
becomes heavily charged with sulphuretted hydrogen. 
- At the time of the visit ‘a strong north-east wind prevailed which, 
together with the spring tides, had cleared the shore of most of the 
