CHAPTER II. 



APPARATUS, MATERIAL, AND REAGENTS 

 EMPLOYED IN A BACTERIOLOGICAL LABORATORY 



(A) HISTOLOGICAL APPARATUS. 



Microscope. For the investigation of micro- 

 organisms a good microscope with oil-immersion 

 system and a condenser, such as Abbe's, is 

 essential. Such fnstruments are supplied by 

 Leitz, Zeiss, and Hartnack in Germany, and 

 Powell and Lealand in England. Zeiss' micro- 

 scope, with -fj and T *g- oil-immersion lenses, or 

 Powell and Lealand's with -^ and -fj, is recom- 

 mended for investigators; while Leitz', with ^ is 

 a serviceable and economical one for students.* In 

 addition to the usual microscopic fittings, Zeiss 

 supplies a micrometer eyepiece, with directions 

 for use. Some such arrangement is essential for 

 the measurement of bacteria. Other accessories to 

 the microscope are- 



A large bell-glass for covering the microscope when not 

 in use. 



About a foot square of blackened plate-glass. 



* Leitz' with ^ costs about 1$ ; Zeiss', with the same, 

 and with iV, 20 more. Refer to foot-note on p. 44. 



