BACTERIA, OR SOIL FLORA 23 



verted into vinegar, and so on in instances too numerous to 

 mention. 



Experiments made go to prove that this power exists in 

 certain substances which are secreted by the protoplasm in 

 their cells. Certain bacteria have been ground up to a fine 

 powder and subjected to enormous pressures. The juice 

 derived from them was thereafter found to have all the potency 

 in effecting chemical changes that the bacteria possessed them- 

 selves. This, however, is not conclusive evidence, as the 

 microscopic spores might very well escape. Indeed, the late 

 Professor Tyndall, Professor Bastian and others found that both 

 very low and very high temperatures failed to exterminate 

 certain bacteria with which they experimented, although their 

 activities were suspended till normal conditions were resumed. 



By the addition of organic manures the number of these 

 beneficial bacteria and their activity can be enormously in- 

 creased and the fertility of the soil much added to. 



The presence of lime in the soil has a very important bear- 

 ing on the freedom with which the bacteria can act. The 

 addition of lime, where the soil is poor in that constituent, or 

 where the soil is soured, or, as in the case of clay, is heavy, has a 

 most beneficial effect. Basic-slag serves the same good pur- 

 pose. In fact it may be definitely stated that the nitrifying 

 power of the bacteria present in the soil is the factor limiting 

 its fertility more than anything else. 



Rubber-planters have hitherto paid scant attention, or 

 none, to this important matter. Yet all vegetation depends 

 for its very existence on the assistance given by the bacteria. 

 The knowledge of this fact ought, at least, to stimulate a desire 

 to see that the soil is maintained in the best condition for 

 promoting the activity of these beneficial bacteria. Water- 

 logged, sour, dank soils encourage the presence of detrimental 

 bacteria, which destroy the fertility of the soil, and also the 

 presence of organisms which feed on beneficial and other 

 bacteria and reduce their numbers, and therefore such con- 

 ditions of soil should be avoided. 



Drainage and cultivation are the chief and best means of 

 ensuring the increased presence and the activity of beneficial 

 bacteria. 



When the rubber trees are too closely planted it is almost 



