258 



BACTERIA IN RELATION TO PLANT DISEASES. 



Table 40. Growth of Strain A 2 T in Glycocoll-glucose Solution after Inoculation with a Small and a 

 Large Loop of Culture Fluid, the Latter Carrying about 5 times as many Bacteria as the Former 

 {Tubes in Sets of 3). 



Table 41. Time of Clouding in Neutral Glycocoll-glucose Solution when Inoculated with Variable 

 Numbers of Sumalran Tobacco Bacteria (10 Tubes used in each Case). 



This disease has now been observed in Sumatra in 15 species of plants belonging to 

 five families. The author summarizes his conclusions as follows : 



1. With a great number of carbon and nitrogen foods B. solanacearum shows growth only in a 

 part of the cultures inoculated. 



2. Light and temperature have no influence, and small variations in alkalinity have slight 

 influence on this variability. 



3. More cultures succeeded after a larger quantity of inoculating material was used. Only a 

 very slight number of individuals, one out of many dozens, is in condition to adapt itself to the new 

 nutrient conditions. 



4. The phenomena fall under the concept of modification; the acquired peculiarities are not 

 constant, when the bacteria are once more inoculated into tobacco, reisolated, and again brought 

 into the same solution. 



There is perhaps another explanation for the variable behavior of this organism in 

 unfavorable solutions, viz, accident. On this supposition all the bacteria are equally capable 

 of growth, but only those actually grow which happen to be lodged under the protecting 

 cover of their fellows, *. e., those in the center of small pseudozoogloese masses. If no masses 

 large enough to protect the first stages of growth are introduced then those particular tubes 

 will remain sterile. This is indicated to me by the fact that Honing often observed the 

 first indications of growth in glycocoll solutions "as little points on the wall of the tube 

 which may grow slowly for some days before the fluid begins to be clouded." Glycocoll 

 solution was used because Bad. solanacearum was easily identified in it on account of the 

 development therein of the peculiar chains and involution forms already described. 



(10) ON THE DECAY BACTERIA FROM SLIME-SICK TOBACCO, DJATTI, AND SOME OTHER OF THE 



SLIME-SICK SUSPECTED PLANTS. 



In December 191 2 Honing published another paper, with the above title, in which he 

 reported on the common bacteria found by him in Sumatra associated with the bacteria 

 causing wilt of tobacco and other plants, but themselves not able to cause any disease when 

 inoculated into tobacco. The following sorts were isolated and studied by him and the 

 new species are described: 



