LABORATORY STUDIES 169 



(It) Amons the many hacteriii of esi)ccial iiitcroHt to us are 

 the following: 



1. Clover-nodule bacteria (Psendomonas leguminosarum) , 

 which enrich the soil by the i^'oduction of nitrogen compounds. 



2. Sulphur-bacteria (Bcggiatoa aiha), which occur as large 

 motile filaments in refrigerator drains. 



3. Apple and i)ear 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 tumcfaciens) , 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. S. West, A Treatise on the British Freshwater Algae, 



Cambridge, 1904. 

 Josephine E. Tildex, The Myxophyccae of North America and 



Adjacent Regions (Vol. I of Minnesota Algae), Minneapolis, 



1910. 

 G. B. De Toni, Sylloge Algarum, Vol. 5, Padua. 

 E. F. Smith, Bacteria in Relation to Plant Diseases, Washington, 



I, 1906; II, 1911. 

 W. D. Frost and E. F. Campbell, A Text-hook of General 



Bacteriology, New York, 1910. 



