OF THE MARINE ALGA2. 
97 
the Biyopsis species, of the Polysiphonise and Callithamnia, 
nay, even the curious apices so characteristic of the genus 
Ceramium, all yield to this mode of treatment, especially if 
it be aided by a hair pencil loaded with water and drawn 
slowly among the finer portions of the plant, should any 
of them still continue to cling together. This operation 
having been satisfactorily performed, the next thing is to 
withdraw the water. Here the syringe again comes into 
play, but this time as a suction pump. It is only necessary 
to place its open end between the larger branches, and by 
very slow movements of the piston the whole of the fluid 
will be drawn up through the barrel, and can be discharged 
into the plate. The eye will determine when the water has 
been sufficiently abstracted, but the ear is a still better 
guide. As soon as a bubbling sound is heard in the body 
of the instrument, it is a certain indication that air is taking 
the place of the water, and that the latter is exhausted. 
To empty the dish entirely it must be gently tilted on the 
side which holds the root end of the plant, so that the 
water shall flow towards the opposite side, where it may be 
drawn off with the syringe. The water having been thus 
got rid of, the operator will probably find it necessary to 
give a final touch with a hair pencil to some of the branch- 
lets or filaments that have been displaced, especially if 
examples of the more delicate kinds be under treatment ; 
the whole may then be lifted out of the dish and laid upon 
blotting paper, to undergo a sort of preliminary drying. 
Although this process takes some time in describing, it 
is in point of fact of the simplest kind, and allows of each 
preparation being got ready in a very short space of time, 
because the operator works upon a firm, even basis ; both 
his hands are free, and there is no large quantity of water 
to be displaced by a chance blow or shake, all which 
advantages are wanting in the ordinary method of pre- 
paring specimens in a plate or basin. 
The preparation must not be left too long exposed to 
the action of the atmosphere, or it will be spoiled. The 
H 
