138 THE SPIRIT OF THE SOIL 



when placed in the ground, should have a suitable 

 medium in which to work. The principle is one 

 universally recognized in Nature. The young em- 

 bryo in the seed is sent out by the parent plant with 

 a stock of food material that makes it independent 

 for several days of the soil on which it falls. In the 

 egg the embryo starts its life with a store of material 

 ready for its needs several thousand times greater 

 than itself. In the mammal the young embryo 

 develops firmly fixed to its parent, and even after 

 birth, by the strength of the maternal instinct, 

 Nature insures that it shall have for months to come 

 an abundant supply of the food that it requires. 



Nitrobacterine was a compromise between the 

 earlier system of the Germans and Americans and 

 that used with bacterized peat. In the cotton-wool 

 preparations the bacteria were sent out with no 

 food-supply to nourish them, and many of them died 

 before ever they reached the land they were intended 

 to fertilize. Nitrobacterine (earth impregnated with 

 bacteria) through the humus it contained, insured 

 that the bacteria should have some food to support 

 their life during the period of waiting ; but the system 

 of utilizing them carried with it the objection that 

 on being applied to the soil they had at once to 

 secure their food from the ground in which they 

 found themselves. The failures with the prepara- 

 tion showed that an important factor had been 

 neglected, and, unconsciously to some extent, the 

 laboratory workers were thrown back to imitate the 

 system followed by Nature in the egg and seed. 

 Peat was a substance rich in the raw material of 



