4o8 EFFECTS OF CLIMATE AND SOIL ON CONFORMATION. 



limestone region bleak and poor ; but in this particular 

 instance it is more or less due to the fact that the lime- 

 stone rock is overlaid with a deep drift accumulation " 

 (McConnell). Lucerne, to grow well, requires a good 

 supply of lime, which in this case will fulfil its purpose, 

 if it is within a short distance of the surface, although not 

 actually in the surface soil, because the roots of this plant 

 can penetrate to a comparatively great depth. 



Plants obtain their nitrogen from the soil by means of 

 their roots, and chiefly in the form of nitrates. In this, 

 they are greatly aided by organisms which are in the soil, 

 and which convert nitrogenous matter into nitrates. Vino- 

 gradski states that these nitriferous microbes cannot do 

 their work efficiently, if carbonate of lime is not present 

 in the soil. 



We have seen (p. 22) that about two-thirds of bone 

 consists of salts of lime. 



Absence of lime in comparatively dry soil appears to 

 have a well-marked effect in keeping down the height of 

 horses, as we see in the ponies of Dartmoor, Exmoor, Wales 

 and Scotland ; allowing of course for the effect of climate. 

 Although the County of Kerry (Ireland^ has a com- 

 paratively warm climate, owing to its southern position 

 and the proximity of the Gulf Stream ; it produced, fifty 

 years ago, great numbers of small ponies, which now have 

 been "improved" into cobs or horses, in order to meet 

 modern requirements. As far as I can remember, these 

 Kerry ponies, many of which I rode and drove when I was 

 a small boy, did not. exceed 13 hands in height. x\s the soil 

 of Kerry is chiefly Devonian, the comparative absence of 

 lime in it was no doubt the cause of the diminutive size 

 of the ponies. Deficiency of lime in soil also appears to 

 reduce the size of "bone" (p. 24) of horses. Thus, the 

 ponies of Wales, the soil of which is chiefly Silurian and 

 Granite, are often " fight below the knee," and consequently 

 they are, as a rule, better suited for harness than for 

 saddle. In some parts of Wales there is a good supply 



