WORK OF BACTERIA 



53 



and supplies him with artificially grown bacteria with 

 which he may inoculate the soil or seed. If the soil 

 is favorable otherwise, the crop is greatly increased 

 and in time the soil made more profitable for other 

 crops. 



The wise farmer does not plant potatoes or corn 

 in the same piece of ground two years in succession, 

 unless he adds large quantities of fertilizer or plant 

 food. He rotates his crops because different species 

 of plants take from the soil different kinds or amounts 

 of food. 



Even if these two fields of work scavenging and 

 aid in agriculture were all in which we make use of 

 bacteria, their claim of helpfulness would be over- 

 whelmingly proved ; but other results of decomposition 

 processes are valuable in the arts and in the commerce 

 of the world. 



By the action of bacteria upon the whitish juice of 

 certain plants fermentation processes are set up which 

 result in the blue indigo so important in dyeing indus- 

 tries. Our grandmothers would have been surprised 

 indeed had they understood that their solid bluing was 

 once a white liquid. 



Bacteria, too, make possible the retting of the flax, 

 whereby the fibres are separated from the stalk to be 

 finally woven into the beautiful "pictures in white" 

 we call table damask. 



They bear their part in the preparation of sponges 

 and in many processes of tanning and tobacco curing. 



Rotation 

 of Crops 



