66 



THE MICROSCOPE 



I, 



) 



The motor is supplied witk flexible connecting wire and 

 plug adapter, so that it can be connected with any ordinary 

 lamp fitting. 



The machine can be made to suit any voltage specified, and 



for direct or alternating current; in the latter case, the phase, 



cycle, etc., must be given. 

 Pipettes. Pipettes (Fig. 69) are small glass tubes of various shapes, and 



are useful for taking specimens out of fluid and transferring to the 



sHp or object-holder 

 for examination. If 

 the upper end of 

 the tube be closed 

 with the finger, the 

 lower end can be 

 immersed in a fluid, 

 and the air within 

 the tube prevents 

 the entrance of the 

 liquid. On removal 

 of the finger from 

 the upper end, the 

 fluid enters the glass 

 tube, carrying with 

 it small bodies sus- 

 pended in it; by 

 replacing the finger, 

 the fluid wiU. be re- 

 tained in the tube, 

 and thus transferred 

 to a sUp, live box, 

 or compressor. Two 

 inatrmnents. or three needles, a pair of fine forceps, a pair of scissors, and a 



scalpel are required for the manipidation of unmoujited objects 



before examination. For the collection of aquatic organisms 



from either fresh or salt water, a coUectiag stick and net are 



of great use. The net is made of fine bolting cloth, and is of a 



conical shape with a glass bottle secured to its apex (Pig. 71). A 



surface net that is towed behind a boat may be made in a similar 



manner, and should be provided with a 



small caHco bag attached to its front edge 



which may be filled with stones to enable 



it to be towed along when sunk below the 



surface of the water. 



Most of the free swi mmin g fauna in 



open water are near the surface during the 



day, but there is often a great variation in the fauna to be 



found at difierent levels. 



II 



Fig. 70. — ^Dissecting Instruments. 



Oollectliig 

 net. 



Fia. 71.— No. 3460, 

 Collecting Net. 



