314 The Botanical Gazette. — [October, 
To secure the samples of water from any desired depth, 
these vacuum tubes are attached to a holder by means of an 
ordinary clamp, the small drawn out glass tube being so ar- 
ranged that the point of it lies near the connecting line that 
is fastened to the holder. When the holder with the vacuum 
quite sufficient, except where pure ‘‘live” sand is presen 
hold the mud column in the tube. of a 
The mass of mud is removed from the tube by water me 
piston rod, and from the center of this mass a known a ee 
of the material is extracted by means of sterilized pn “This 
For this purpose a small sized cork borer is well Pasi Jume 
nown volume of mud is then diluted with a sce 
of sterile water and plated as in the other case. ; 
