36 MYCOLOGY 



London in 1665 in which 70,000 persons perished. It is carried b\ 

 infested rats. 



N on-palhogcnic: B. aceticum sets up in alcoholic solution the acetic 

 acid fermentation and its films later form mother of vinegar. B 

 acidi laclici ferments sweet milk transforming it into sour milk when 

 the acidity is due to lactic acid. B. phosphoreum is a phosphorescen 

 fresh-water organism. 



Bacillus (Cohn char, emend.). — Cells straight, rod-shaped to ovoid 

 long or short, sometimes united into filaments. Motile by wavy 

 bent flagella scattered over the whole surface of the cell. Formatioi 

 of endospores frequent. Motility may be active for a time, and thei 

 is lost. Pathogenic: B. mus<z causes the Trinidad banana disease 

 B. tracheiphilus is responsible for the wilt of cucurbitaceous plants 

 B. amylovorus , the pear-blight organism; B. carotovorus, specific ii 

 soft rot of carrot; B. aroidecB, an organism which causes soft rot of thi 

 calla; B. telani, the causal microbe in tetanus, or lockjaw, is found ii 

 the soil and may enter the skin or superficial muscles of man through ; 

 pin prick, or rusty nail point; B. typhi, the typhoid bacillus. Non 

 pathogenic: Bacillus subtilis, the hay bacillus found in hay infusion, an( 

 is the cause of decay. B. coli in the alimentary canal of animals an( 

 men and in the water polluted by sewage. B. butyricus produce 

 butyric acid fermentation and the coagulation of casein. B. radicicoU 

 (= Rhizohium leguminosarum) lives in the roots of leguminous plant 

 and forms the root tubercles or nodules (Figs. 8, 9, 10). B. amylobacte 

 (= Clostridium butyricum) ferments cellulose, dissolves casein and i 

 useful in the retting of plants for fiber production. B. prodigiosu 

 is found on many food substances imparting to them a dark red color 

 B. calfactor appears in hay infusions, where it produces a rise of tem 

 perature. B. putrificus, a widely distributed organism. Many bacill 

 that occur in the ocean are luminous. 



Pseudomonas. — Cylindric bacteria, sometimes long, sometimes short 

 occasionally in threads. Locomotion accomplished by polar flagella 

 the number of which may vary from one to ten, most frequenth 

 one flagellum is present, or three to six. Endospores are formed, bu 

 are rare. The following are the causes of diseases in cultivated plants 

 Pseudomonas campestris is responsible for the black rot of cabbage am 

 other cruciferous plants. Ps. hyacinthi causes the yellow disease 

 hyacinths. Ps. vascularum is associated as the causal bacterium ii 



