1892.] 



MICROSCOPICAL JOURNAL. 



31 



and one-qua*rter of an inch wide, cut from the ordinary square,* thin 

 cover-ghiss, are cemented to a slide with Canada balsam, as seen in 

 view A, at l. l. The object is now placed in a large drop of water 

 between these two strips, under a one-inch square cover-glass, and the 

 entire capillary space may be filled, if necessary, by adding a few more 

 drops of water. 



Two short strips of linen, s. s., are now inserted, one at each end, 

 and are held in position bv two rubber bands, passing over the cover- 

 glass and around the slide. In order to secure a flat surface on the 

 under side, the slide is now cemented to another slide by means of two 

 pieces of wax, equal in diameter to that of the rubber bands. 



Apparatus for Controllinc; Living Organisms. 



A glass, shown in view B at k, reaching about three inches above 

 the stage of the microscope, is filled with water, and a glass siphon in- 

 serted, the shorter arm of which has a much smaller opening than the 

 longer. After filling the siphon with water, a strip of linen is gradually 

 forced into the longer arm, till the flow, of water is reduced to dropping. 

 The linen strip is now^ cut the required length, and connected with one 

 of the short pieces at the side of the cover-glass. The water glass may 

 be covered to exclude any particle of dust. In this way a constant and 

 steady flow of water is secured. The overflow is carried, by means of 

 another linen strip, from the opposite end of the cover-glass into a small 

 receptacle (" waste" in the diagram) at the foot of the microscope. 



