ILLUSTRATIONS 



FIGURE PAGE 



i. Pasteur at the Age of Twenty-one . . facing 18 



2. Right-handed and Left-handed Crystals of 



Tartaric Acid , . 27 



3. Forms of Protozoa 47 



4. Cells of Yeast 50 



5. Forms of Bacteria 51 



6. A Test Tube Plugged with Cotton and Showing 



a Bacterial Colony Growing in the Culture 

 Medium 57 



7. Flask with Curved Neck Used for Keeping Boiled 



Infusions Supplied with Air Free from Germs 91 



8. Flask with Sealed Neck Partly Filled with 



Boiled Infusions 93 



9. Apparatus Designed to Free Air from Germs by 



Drawing It Through Sulphuric Acid . . .103 



10. Apparatus Designed by Tyndall for Freeing Air 



from Floating Matter 105 



11. Organisms Found in Diseased Wine .... 122 



12. Pasteur in His Laboratory .... facing 165 



13. Pasteur and Madame Pasteur . . . facing 230 



14. Tomb of Pasteur facing 241 



