APPENDIX 



DIRECTIONS FOR LABORATORY EXPERIMENTS 



Apparatus. The experiments here described are all of a simple 

 character. Many of them can be performed without any special 

 apparatus ; but some would need, in addition to test tubes, flasks, and 

 other simple glassware found in any 

 laboratory, a few pieces, as follows. 



1. A steam sterilizer. An ordinary 

 steamer such as used in the kitchen 

 will do. A better form is shown in 

 Fig. 81. 



2. A hot-air sterilizer. The best form 

 is shown in Fig. 82. Some sort of sheet- 

 iron box which will serve the purpose 

 may be found in almost all chemical 

 laboratories. 



3. Petri dishes. These are double 

 glass dishes, Fig. 83, several dozen of 

 which should be at hand. 



4. Glass pipettes to hold i cc. 



5. A few fermentation tubes, shown 

 in Fig. 38. 



6. Pieces of platinum wire fused 



into glass rods are convenient for transferring bacteria. 



7. To carry out the microscopic studies there will be needed a 

 microscope with a two-thirds and a one-sixth inch objective. A higher 

 power is desirable though not necessary. In addition, glass slides 

 and cover glasses will be needed. 



The apparatus above listed (except the microscope) costs little, 

 and many of the experiments can be performed with even simpler 



improvised material. 



267 



FIG. 8 1. Steam sterilizing 

 apparatus. 



