154 bacteria in relation to plant diseases. 



Nomenclature and Classifications. 



The nomenclature of the bacteria is in a somewhat chaotic state, as might be 

 expected of a science which has been cultivated so largely by medical men and so 

 comparatively little by systematic botanists and zoologists. The writer therefore 

 will venture a few remarks on this subject. 



If an organism is distinct from any which has been described, so as to be 

 regarded as a new species or spoken about as a distinct thing, then it should be given 

 a specific lyatin name and not designated by a figure or a letter of the alphabet. 

 Bacillus No. i, 2, or 3, or A, B, C, is proper enough for private memoranda while 

 an investigation is incomplete, but when it is finished and ready for publication 

 these designations should give place to scientific names. 



Naturalists everywhere are in agreement that the scientific name of a living 

 thing should consist of two words onl}' — the name of the genus, followed by the 

 name of the species, after which is usually added the name of the author, or, if a trans- 

 position has been made from one genus to another, the name of the original describer 

 is put into a parenthesis, followed by that of the transferrer outside of the parenthesis. 

 All polynomials, of which there are now many, are to be regarded as nonima exclii- 

 denda. For example. Bacillus coli cojnvmnis should give place to B. coH, and such 

 names as Bacillus mcmbranaceus amcthystiims mobilis^ Bacillus argenteo phosphor- 

 esceiis liquefaciens^ Bacillus pyogenes foetidus lique/aciens, should yield to something 

 shorter and more in conformity with modern views of nomenclature. More than 

 170 trinomial names are to be found in the last edition of Fliigge's Mikroorganis- 

 men, and very few, if any, of them were given with the distinct idea that they repre- 

 sent varieties of other organisms. The habit of giving trinomial or quadrinomial 

 names should be abandoned, and as far as possible binomial names should be sub- 

 stituted for those already in literature. 



In the period antedating Koch's discovery of the poured-plate method, when 

 there was no very satisfactory way of separating one organism from another so as 

 to have pure cultures, the descriptions were necessarily vague. They were usually 

 drawn from mixed cultures, and very brief descriptions were supposed to be ample. 

 The result is that many of the names which have come down from this period are 

 nomina iiuda, or semi-nuda, i. <?., it is impossible to associate them with any known 

 organism for the very good reason that they were not founded on any one organism, 

 but on mixtures now indeterminable, or were too imperfectly characterized. Gen- 

 erally speaking, such names should be abandoned. The only safe rule and the only 

 just one is to discard all specific names which do not carr}' with them an exact 

 statement or description, sufficient to associate the name beyond doubt with a par- 

 ticular organism. It is not sufficient description of an organism to say that it is 

 the cause of a disease, unless the author has proved it to be such according to the 

 well-recognized rules of pathology. In order that his name shall hold, an author 

 must have carefully described the disease and must have proved in some way the 

 pathogenic nature of his organism, or else he must have given a fairly correct descrip- 

 tion of the morphology and physiology (cultural characters) of the organism, so that 

 it can be detected anywhere. Just how much shall constitute a sufficient description 

 must depend on circumstances. A few lines might be sufficient if the description 



