INDEX 
Acetic acid, sugar changed to, 
61 
Acid, butyric, 62 
Acids as preservatives, 72 
Acquired immunity, 94, 134 
Agar for dust gardens, 10 
Alcoholic fermentation, 114 
Alexines, 93 
Animalcules, 109 
Antiseptics, 65 
Antitoxin, 94, 137-144 
diphtheria, 95, 138 
Artificial immunity, 94, 136 
Bacteria, 16-32 
as scavengers, 48 
classed as plants, 112 
definition of, 16 
disease producing, 75 
effect of cold on, 90 
excretions of, 18 
experiments with, 64 
food of, 20 
forms of, 17 
growth of, 22 
harmful, 63 
in cheese making, 60 
in coarse meals, 45 
in “eyes” of potato, 45 
in ice, 85 
in milk, 14 
in school rooms, 107 
liquefying, 74 
method of study of, 112 
natural home of, 30 
nitrifying, 51 
on dust particles, 97 
secretions of, 31 
size of, 23 
structure of, 17 
useful, 47 
with flagella, 27 
work of. 47, 54 
Bacteriology, history of, 109- 
113 
lessons for children, 124 
Barriers of the body, 129 
Bed-making, 102 
Blood poisoning, 91 
Body, barriers of the, 129 
Boiling clothes, necessity for, 
30 
Bread, baking, 45 
leavened, 6 
Breeding ground for germs, 77 
Brushing clothing, 106 
Burn infected material, 116 
Burning sweepings, 104 
Butter bacteria, 55 
bad flavors in, 58 
making, 55 
Butyric acid, 62 
Canned goods, 70 
Carelessness, criminal, 83 
Care of discharges in disease, 79 
Of plumbing, ro6 
of refrigerator, 29 
165 
