392 The Botanical Gazette. [October, 
two localities examined must be explained in some other 
As yet, we do not possess sufficient knowledge concerning 
the distribution of bacterial life to satisfactorily explain this 
peculiarity. 
Relation of the bacteria of the sea bottom to the superposed 
water masses. 
The idea was advanced as a result of last year’s tests that 
the high content of mud when compared with water was in 
part due to the growth of distinct species that were to be 
found only in the mud. This indigenous flora was in no way 
derived from the water masses above but had spread itself 
over the sea bottom in a way not at present thoroughly 
understood. This theory was based upon the fact as deter- 
mined by cultures that at least 35 per cent. of the total bac- 
terial contents of the Mediterranean mud in the vicinity of 
‘Naples was included in three species that were exclusively 
slime bacteria. 
The work this season afforded an opportunity to test the 
correctness of this view on data froma widely different source 
e idea has already gained some ground that the soil we 
toms of the oceans have derived their bacterial contents from 
the water mainly as a result of sedimentation. ee - 
This result is based upon the fact that while river se 7 
is usually rich in germ life, lake water is poor; therefore Vife . 
inevitable that the mud must have derived its bacteria 
from the lake water by. sedimentation. ‘chness 
Practically no data had ever been gathered on the 1 tite 
of either lake or sea bottoms in bacterial life from a gage 
tive standpoint so that the conclusion was mainly ai not 4 
one. The results of experimental sedimentation gs a : 
show that bacteria have any decided tendency pstecee! | 
sition. The self-purification of polluted streams_ now ac- 
to be explained upon the theory of sedimentation siti ex- 
: re have no po : 
counted for largely in another way and w all these micto- : 
year, and indicate beyond a doubt that a 
the bacteria in the mud are inhabitants so tare embrae 
The majority of the individual germs presen ; 
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