. Bacteria in relation to plant diseases. Bacteriology; Plant diseases. GENERAL CONSIDERATIONS. ON THE SUPPOSED NORMAL OCCURRENCE OF BACTERIA IN PLANTS. We now believe that bacteria do not occur normally in the interior of sound plants. The case is quite different, however, with wounded plants or wilted ones. Frequently sapro- phytic bacteria have been found in such plants and occasionally mistaken for parasites. When bacteria are found in the tissues of plants in any great number we may assume that they are disturbing elements, and that if they continue to multiply the result to the host or s
. Bacteria in relation to plant diseases. Bacteriology; Plant diseases. GENERAL CONSIDERATIONS. ON THE SUPPOSED NORMAL OCCURRENCE OF BACTERIA IN PLANTS. We now believe that bacteria do not occur normally in the interior of sound plants. The case is quite different, however, with wounded plants or wilted ones. Frequently sapro- phytic bacteria have been found in such plants and occasionally mistaken for parasites. When bacteria are found in the tissues of plants in any great number we may assume that they are disturbing elements, and that if they continue to multiply the result to the host or some portion of it must be some considerable diminu- tion of vitality, even if no specific disease supervenes. Compen- sations due to symbiosis are not here under consideration. The former great uncertainty as to the life-history and habitat of bacteria led to many speculations respecting their normal occur- rence in the interior of both plants and animals. The belief that they might occur normally in the interior of plants arose from the inexact observations and experiments of various early workers, notably Bechamp and Hallier. The dispute continued for a number of years but was finally settled in the negative. Bechamp went so far as to maintain that his microzymes were always present in plants and animals, were in fact the simplest components of the tissues and led an independent life after their death and disintegration. Hallier believed that the protoplasmic granules of fungi were converted into bacteria capable of an inde- pendent existence.* Fremy maintained the existence of hemi- organized bodies in the juice of fermentable substances which bodies were converted into yeasts. Trecul believed in similar transformations: granules of organic matter became motile bac- teria. In a later time it was still believed by some that bacteria could be cultivated out of the sound interior of plants and animals and were normally present therein, and by others that they arose spontaneousl
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