170 Tue Microscope. 
Desmids and similar objects from the foreign matter with which 
they are associated in nature, that a few directions may not be 
amiss. The following method, although extremely simple, is 
new to me and as I have seen no hint of the same in any of the 
common microscopical books or journals to which I have access, 
I trust that it will prove new and valuable to some of the 
younger readers, at least, of THe MrcroscoprE—such as must 
draw their methods either from these popular works or from 
their own experiments. 
I use for separation, etc., a set of suction-tubes, five in num- 
ber, increasing and decreasing in fineness from No. 3, which is 
large enough to comfortably admit a cosmarium tetraophthal- 
mum. These are ranged on a small wooden rack plaeed on a 
box of convenient size at the right of the microscope and are 
fitted in, as needed to a small fiexible white rubber tube; this 
fits over one of two glass tubes put tightly through the stopper 
of a1 oz. wide-mouthed bottle and to the other tube is fitted a 
second one of rubber which is held in the mouth while at work 
or fitted to a convenient mouth piece. The tubes are filled with 
water on beginning work to a height sufficient to satisfy capil- 
lary attraction. Then, working e. g., under lin. objective, 
B eyepiece, the point is brought nearly to surface of pool on 
slides and moved to-and-fro horizontally till shadow is seen in 
field ; thence quickly brought with point close to object. After 
a little practice the proper point can be inserted and instantly 
brought to object without taking the eye from the field. It can 
now be sucked in and transferred to little pools of 50 p. c. gly- 
cerine on a “ collecting slide,” parcelling off like forms, differ- 
ent sizes, etc., or, by alternately expelling and drawing in the 
breath, the object can be rolled over and over by the current 
from the tube thus showing all sides. 
I ordinarily take samples with a small pipette, place on 
slide and spread out and break up foreign gelatinous masses 
with a curved glass needle set in a match stick as a handle. I 
first give a preliminary running over with 50.100 diameters for 
larger forms and then, taking care that the pool is shallow 
enough to avoid contact with objective and occasionally re- 
placing water lost by evaporation, run down with 4 in. or 4 in. 
objective and take out the smaller species. Finding, for exam- 
