ON COLLECTING ANIMALCULES. 6.9 



"bj the 'figure,— this prevents the water from entering the tube ; and 

 when the end is near to the object which it is wished to obtain, the 

 finger is to be quickly removed and as quickly replaced. The moment 

 the finger is taken off, the atmospheric pressure ■^ill force the water, 

 and with it, in all probability, the desired objects, up the tube. When 

 the finger has been replaced, the tube containing the fluid may be 

 withdrawn from the phial ; and as the tube is almost certain to con- 

 tain much more fluid than is requisite, the entire quantity must be 

 dropped into a watch-glass, which spreads it, and the insect may be 

 again caught by putting the tube over it, when a small quantity of 

 fluid is sure to run in by capillary attraction. This small quantity is 

 to be placed upon the tablet ; but should there be still too much for 

 the tablet, if it be touched with the tube again, it will be diminished 

 accordingly. If we wish to place several individuals together on the 

 tablet, it is necessary that each should be taken up with the smallest 

 amount of water : to effect this, Mr. Varley suggests that the tube 

 should be emptied on a slip of glass, in separate drops ; and with one 

 of the capillary tubes but little larger than enough to catch them, they 

 may be lifted out one by one, and be placed on the tablet. Generally 

 speaking, it ia necessary to add a small quantity of vegetable matter 

 to animalcules, to keep them alive ; and as many species of them are 

 found on confervas and duck-weed, some instrument is required to take 

 small portions of these plants out of the jar in which they are growing. 

 For this purpose Mr. Varley uses the forceps fig. 48. These are made 



fig. 48. 



of brass ; the points are a little curved, to keep them accurately toge- 

 ther, and the blades are provided with a hole and steadying-pin. This 

 instrument serves for transferring small portions of vegetable matter, 

 or for picking up minute objects. 



Collecting Animalcules. — For collecting the living water animalcules, 

 the cambric-muslin net, made similar to a landing-net, fig. 49, will be 

 found very useful ; this should be secured to a brass-ring a, and fitted 

 into a socket b, by which it can be attached to the end of a walking- 

 stick, or, when not in use, the socket may be carried in the pocket ; and 

 the net, by contracting the diameter of the ring (which the construction 



