IO 
Garden Work 
In trenching clay soil, ridging may be done. Standing 
sideways, put one spit on one side, and one on the other, 
without breaking in any way. This leaves a deep furrow 
between the ridges, and exposes a greater area to frost, &c. 
Sandy soils should not be dug till spring. If dug 
early it increases its porosity, and any soluble plant food 
left in the soil is washed out by the winter rains. 
THE LIVING SOIL 
During recent years it has been discovered that the 
soil is inhabited by countless numbers of minute organisms 
called bacteria. Bacteria are simply one-celled organisms, 
and measure one micromillimeter in length. A micro- 
millimeter is x jfo o mm., or about ^5-^00 i n - They are of 
various shapes: round, called coccus; cylindrical, called 
bacillus; and spiral, called spirillum. 
These lowly organisms do a vast amount of work in 
the soil. They attack the manure which is placed there, 
and convert it into liquid plant food. Without such 
organisms in the soil our fields and gardens would become 
quite barren. It is therefore necessary for us to see that 
these bacteria are enabled to work freely, and to multiply 
rapidly. Some are provided with hairs or flagella. By the 
lashing movements of these they are able to travel about 
in the moisture between the particles of soil, and so are 
enabled to do more work. The majority of these minute 
organisms require oxygen for their successful development. 
This shows how important it is that the soil should be 
thoroughly aerated. They also like a slightly alkaline 
medium. If the soil becomes too acid by over manuring, 
