BACTERIOLOGICAL TECHNIQUE 



17 



VII. NUTTALL'S MICROSCOPIC THERMOSTAT. 



This simple apparatus is adapted 

 for use with different microscopes 

 that are placed in the thermostat 

 from behind, the top of the ap- 

 paratus, which is slanting, consist- 

 ing of two laterally movable slides, 

 the inner margins of which are made 

 of strips of felt cut according to the 

 shape of the microscope, so that the 

 tube and adjustment remains out- 

 side. On the left side is an aper- 

 ture large enough to admit the 

 hand, by which the slide can be 

 manipulated. In front is a window 

 admitting the light. On the right 

 side screws connected with the 

 mechanical stage can be adjusted ; 

 such an arrangement is, however, 

 not usually necessary, and also in- 

 creases the price. The thermostat 

 is closed by a door at the back. 

 This apparatus is useful for study- 

 ing bacteria or protozoa in drop 

 cultures, and has also been found 

 useful in studying zooparasites. 



FIG. 6. Nuttall's Microscopic Thermostat. 



VIII. THE COVER-GLASS SPECIMENS. 

 ORDINARY METHOD. 



1. Place a drop of sterile water on a clean cover-glass with a 

 sterilized platinum loop. 



2. Inoculate the drop with a small quantity of the material under 

 investigation mixed and well spread with the platinum loop or wire. 



3. Allow the materialon the cover-glass to dry in the air. 



4. Fix, by passing the cover-glass, preparation side uppermost, 

 through the Bunsen flame three times at intervals of one second, the 

 cover-glass being held with ' Cornefs Forceps. 1 



5. Stain the specimen by flooding with the desired filtered stain, 



B 



