BACTERIA IN RELATION TO PLANT DISEASES. 



BY ERWIN F. SMITH. 



PART I. AN OUTLINE OF METHODS OF WORK. 



GENERAL REMARKS. 



The following outline of methods for the study of bacterial diseases of plants, 

 which are now in use in the Laboratory of Plant Pathology, United States Depart- 

 ment of Agriculture, has gradually assumed its present shape as a result of the 

 writer's field, hot-house, and laboratory experiments during the past thirteen years. 

 In nearly the same shape, so far as arrangement is concerned, but in a less complete 

 form, it was published in the American Naturalist in 1896.* 



The scheme here presented is entirely practicable and is believed to be not more 

 extended than the exigencies of the case require ; in the interest of better methods 

 of work in plant pathology it is recommended to all who contemplate a special 

 study of bacterial diseases of plants, and also particularly to those who intend to 

 describe and name species of bacteria, whether pathogenic or nonpathogenic. Those 

 who doubt the necessity for so much work are advised to read procedures recom- 

 mended for the study of bacteria by a committee of the American Public Health 

 Association, and the earlier paper by H. Marshall Ward (Bibliog., III).| It would 

 be still more to the point if they would isolate a dozen bacterial organisms from the 

 soil, air, or water, ami undertake faithfully to identify them by means of any of the 

 older descriptive works, e. g., Eisenberg's Diagnostik or Saccardo's Sylloge Fun- 

 gorum, or even by such recent manuals as those of Sternberg, Lehmann & Neumann, 

 Fliigge, Migula, or Chester (Bibliog., III). Everyone who has carefully inquired 

 into the matter knows that the brief statement of the behavior of an organism on 

 nutrient agar, on gelatin, and on two or three other media, with perhaps a loose 

 statement of its color and size, no longer constitutes a description which describes. 

 Such accounts, of which there are a great many, usually fail to mention just those 

 things which might serve to distinguish the organism from its fellows. If a new 

 species is not to be described so that it can be identified by others, what then is the 

 use of any name or any description ? The name will only serve to encumber future 

 synonymy and to recall the incapacity of its author. 



*The bacterial diseases of plants: A critical review of the present state of our knowledge, 

 parts i -vi. Am. Nat., August and Septcml>i-r, i 

 fFor Bibliography see end of volume. 



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