Mar. 24, 1919 AmmonificaPion of Manure in Soil 337 



one which does not denitrify. Those who report denitrification either 

 state the organism to be Gram-negative (as do Lehmann and Neumann) 

 or else make no statement in regard to the Gram stain. Those who 

 have found it to be Gram-positive have not studied its action on nitrate. 

 This suggests that two different orgaiusms, one Gram-positive and 

 pathogenic, the other Gram-negative, denitrifying, and probably sapro- 

 phytic. If this be the case, the former is more likely to be distinct from 

 the fluorescens type than the latter. 



PSEUDOMONAS PUTIDA 



Psevdomonas putida (Fliigge) Migula {38, p. 912). The name ''Bacillus 

 ■fluorescens putidus" ^ was given by Fliigge {16) to the nonliquefying, 

 fluorescent type of organism. Eisenberg {14), besides this name, used 

 the name " B. fluorescens nonliquefaciens" for what he considers a dif- 

 ferent organism, and in this is followed by Kruse (26) and Migula (38), 

 the latter discarding the polynomial and renaming it "Ps. Eisenbergi." 

 Lehmann and Neumann (30), however, do not consider it a distinct type 

 and Ps. putida is the only nonliquefying species considered to-day to 

 have good standing. 



Whether Ps. putida and Ps. fluorescens are distinct is also a question 

 that is not entirely settled. Lehmann and Neumann do not question 

 that they are distinct. Pribram and Pulay (41), as the result of their 

 serological studies, conclude that they are not only distinct but that 

 they stand the farthest apart of any of the fluorescent cultures studied. 

 Kdson and Carpenter {13), however, consider that there are so many 

 gradations between rapid liquefiers and nonliquefiers that this charac- 

 teristic can not be used to distinguish between species. 



NUMBER OF FLUORESCENT BACTERIA 



A summary of the literature, therefore, gives no satisfaction in decid- 

 ing how many different pseudomonads possess the property of producing 

 fluorescence in culture media. Some writers consider them all the 

 same; others make two or three different species; still others believe 

 there are several species; while, if we consider every name a distinct 

 species, there are a hundred or more. A study of the literature, however, 

 indicates that there are four or five types standing out more or less 

 distinct from each other: (i) Ps. aeruginosa, the blue-pus organism, a 

 Gram-positive, rapidly liquefying organism, producing the blue-green 

 pigment pyocyanin in addition to the fluorescent pigment, and possibly 

 reducing nitrate to nitrogen. (2) Ps. fluorescens, a Gram-negative, 

 rapidly liquefying saprophyte, showing poor growth or none at 37° C, 



' In the third edition of Fliigge's book, Kruse (26) uses the nanie B. fluorescens putridus, evidently a 

 misprint or mistake in spelling, because Fliigge's description of the organism by the term "slinkende" 

 shows plainly that "putidus" was the word he jneant to use. Migula in renaming the organism follows 

 Kruse's spelling, calling it Ps. putrida (Fliigge). Other writers, however, such as J. Eisenberg {14), Leh- 

 mann and Neumann (jc), and Chester (2) have used the spelUng "putidus." 



106546°— 19 3 



