APPARATUS AND METHODS. 



21 



various methods of fixing up a moist chamber slide. A 

 simple plan is to cement a glass or rubber ring to a slide 

 slides with such rings can be bought ready prepared 



u 



Fig. 12. A Moist Chamber Slide ; on the right, a glass ling which 'can be cemented 

 to an ordinary slide, to form a moist chamber. 



(Fig. 12) ; then place in a small drop of liquid the object 

 to be examined, invert the cover so that the liquid does 

 not get 011 the upper side of the cover, and lay the in- 

 verted cover on the other ground edge of the ring which 

 should be smeared with vaseline 

 to make the chamber air-tight. 



Another plan, even better for 

 many purposes, is to cut a square Fi s- is. A Ward's Tube (Moist 



j i- i c /OJ.T- i. Chamber) which can be cemented 



or round hole 5/8ths of an inch to a slide. 

 in diameter in a piece of card- 

 board l/8th inch thick, 1 inch wide, and l inches long; boil 

 the card to sterilise it the boiling also makes it fit more 

 closely to the slide ; while still wet press the card to the 

 slide, and invert the cover-glass, with its hanging drop, 

 over the hole. 



19. Ward's Tube (Gas Chamber) Slide. This ap- 

 paratus, which is especially suitable for experiments on 



Fig. 14. Gas Chamber Slide ; the side tubes are shown fitted with rubber tubing. 



protoplasmic streaming (see 33-35) and also for cul- 

 tures of pollen- grains, spores, etc., can be bought ready 

 fitted up (Fig. 14) ; or the tube itself (Fig. 13) can be 



