Importance of Nitrogen to Growth of Plants. 



243 



Earthworms. 



During the season of 1906, it was observed that the maize on the 

 Mitchell farm was extremely uneven. Some hills of maize would be 

 large, vigorous, stocky and of deep green color while hills immediately 

 adjacent would be small, spindling and of a decidedly lighter green color. 

 Gilmore, on having his attention called to the possible role of nitrogen, 

 made an examination of these hills. He found that where the hills were 



large they were over a lump of ma- 

 nure while where the hills were small 

 the manure was absent. Figures 83 

 and 84 illustrate the conditions just 

 described. The writer happening 

 along after these hills were photo- 



FiG. 83. — Corn stalk which grew above 

 a block of manure; 48 earthworms 

 were found in the block of earth on the 



- roots. Under another larger stalk. 60 

 worms were found. \ 



Fig. 84. — Corn stalk which 

 grew over no manure. No 

 earthworms were found in 

 the block of earth. Another 

 stalk about the same size 

 had 2 and another a little 

 larger had 18 earthworms 

 and also a little m.anure. 

 On same scale as Fig. 83, 



graphed observed that there were some earthworms clinging to the roots 

 of the larger hill. Notwithstanding this hill had been taken up some 

 hours previously and removed some distance from where it grew, a 

 count showed 48 earthworms at work in the manure and earth clinging 

 to the roots of this hill. The smaller hill was next examined and not an 

 earthworm was found. Examinations were then made of other large and 

 small hills. Even larger numbers of earthworms were found in some of 

 the larger hills and some were also found in the smaller hills but always 

 less in number and smaller in size. 



Were these earthworms incidental, like so many tumble bugs in cow's 

 droppings, or do they play some important part in making plant-food 

 and especially nitrogen available? It is said that in Southern England 



