67 



THE ACTION OF BACTERIA ON HIGHER PLANTS* 



GEORGE MASSEE, F.L.S., V.M.H., etc.. 

 Keuc. 



Although the Bacteria or Schizomycetes are not included in 

 the fungi, they hover around the fringe of this large group of 

 plants, and the two possess certain important features in 

 common, such as the absence of chlorophyll, hence they are 

 either saprophytes or parasites, and their influence on life is 

 very marked either for good or evil as the case may be. As an 

 illustration of the influence of Bacteria may be mentioned the 

 celebrated Harrogate waters, which, but for the work done by 

 these minute organisms, would not exist. The Bacteria are 

 among the most microscopically minute of living organisms, 

 and one of the characteristic features of the group is the 

 liberation of nitrogen, either in the form of this element, or 

 in combination with hydrog"en as ammonia. 



Being so exceedingly minute, the Bacteria do not present 

 that variety of form and structure presented by the so-called 

 higher organisms, and are more frequently recognised by their 

 mode of growth and behaviour under certain conditions of 

 culture than by any structural peculiarities. Some Bacteria 

 are characterised by the production of brilliant colours, others 

 by the emission of odours agreeable or very much the reverse. 

 Some again are aerobic, that is to say, they can only, like our- 

 selves, live and have their being in the presence of free oxygen ; 

 others again are enabled to live and flourish in the absence of 

 free oxygen, and are called anaerobic. These latter require 

 oxyg^en quite as much as the aerobic forms, but are enabled to 

 obtain the requisite amount from various substances containing 

 this element in chemical combination. Finally, many Bacteria 

 are chemotactic, that is, they are strongly attracted, or equally 

 strongly repelled, by the presence of different substances in 

 solution. Such substances need not necessarily be of a nutritive 

 nature. 



The above and other peculiarities illustrate the very varied 

 conditions under which Bacteria can carry on their life-work, 

 which consists mainly in breaking up complex chemical com- 

 pounds, and liberating their constituents into the atmosphere 



* Resume of a discourse delivered at the Helmsley meeting- of the 

 Mycolog-ical Section of the Y. X.U. 

 1904 March i. 



