LABORATORY STUDIES 169 
(hk) Among the many bacteria of especial interest to us are 
the following: 
1. Clover-nodule bacteria (Pseudomonas leguminosarum), 
which enrich the soil by the production of nitrogen compounds. 
2. Sulphur-bacteria (Beggiatoa alba), which occur as large 
motile filaments in refrigerator drains. 
3. Apple and pear blight bacteria (Bacillus amylovorus), 
causing the blight in apple and pear trees. ~ 
4, Cucumber-wilt bacteria (Bacillus tracheiphilus), causing 
the ‘‘ wilt disease” of cucumbers, and other cucurbits. 
5. Crown-gall bacteria (Pseudomonas tumefaciens), causing 
the crown galls in the roots and stems of many plants. 
6. Typhoid fever bacteria (Bacillus typhosus), causing 
typhoid fever. 
7. Tuberculosis bacteria (Bacterium tuberculosis), causing 
tuberculosis. 
8. Diphtheria bacteria (Bacterium diphtheriae), causing 
diphtheria. 
9. Influenza bacteria (Bacterium influenzae), causing influ- 
enza (“‘Grippe’’). 
10. Anthrax bacteria (Bacterium anthracis), causing anthrax. 
11. Cholera bacteria (Microspira comma), causing cholera. 
12. Colon bacteria (Bacillus coli) in the large intestines of 
most mammals. 
LITERATURE OF MYXOPHYCEAE 
Here as elsewhere only the most necessary works are men- 
tioned, in the order of their desirability for the beginner in 
Botany. 
G. 8S. West, A Treatise on the British Freshwater Algae, 
Cambridge, 1904. 
JosEPHINE E. TitpEen, The Myxophyceae of North America and 
Adjacent Regions (Vol. I of Minnesota Algae), Minneapolis, 
1910. 
G. B. De Tont, Sylloge Algarum, Vol. 5, Padua. 
E. F. Smrru, Bacteria in Relation to Plant Diseases, Washington, 
I, 1906; LI, 1911. 
W. D. Frost and E. F. Campsety, A Teat-book of General 
Bacteriology, New York, 1910. 
