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 Béchamp and Hallier. Thedispute continued for a number 
of years but was finally settled in the negative. 
Béchamp 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. Trécul 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 
spontaneously in all sorts of organic substances. That the organic 
must have developed from the inorganic during some period in the 
history of the earth seems probable, but we must look elsewhere 
than to Béchamp and Hallier for evidence. 
The amount of ignorance and credulity respecting micro- 
organisms prevalent in the middle of the last century seems aston- 
ishing in the light of our present knowledge. It is, however, the history of all subjects 
hedged about by difficulties. The beginnings are always foggy. 
Pasteur appears to have been the first to show that the sound interior of plants is free 
from micro-organisms. He experimented on grape-berries, taking some of the juice from 
the interior under such conditions as to preclude the entrance of surface bacteria and 
placing it in sterile must which remained sterile, while flasks treated to the washings from 
the surface of the grapes invariably developed growths of some sort. 
In 1879-1880, Chamberland working in Pasteur’s laboratory showed that beans taken 
directly from the interior of their pods were free from bacteria, 7. e., did not contaminate 
culture-media when put into them (see fig. 2). 
*Even in very recent times we have similar views occasionally coming into print, e. g., Dunbar’s Zur Frage der 
Stellung der Bakterien, Hefen und Schimmelpilze im System (1907), in which it is maintained that bacteria, yeasts 
and fungi, are the product of algal cells. : ’ : ; 
{Fro, a Picas taken loge less than 18 hours after picking and placed on sterile nutrient gelatin where 
they have sprouted and grown entirely free from the presence of bacteria. Photographed Oct. 3, 1908, from sample 
tubes sent the writer by Mrs. A. W. Bitting. Two-thirds natural size. 
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Fig. 2.7 
23 
