GARDEN WALLS 207 



slate or piece of glass, or by inserting them under the 

 shelter of the coping-stones. Their chief enemy then 

 will be the snails, who manage to get at their succulent 

 leaves in spite of the poisonous spines with which they 

 are protected. And, indeed, this is the chief objection 

 to old walls; they are the favourite haunts of many 

 enemies to the garden. In course of time the mortar 

 decays, and the wall is full of holes ; where these are 

 at all large they are apt to get filled with colonies of 

 snails. If the holes are in the lower part of the wall, 

 mice will take possession of them, and I have found 

 slow-worms even in the higher holes, but these do no 

 harm. But it is to the insect world that all the holes 

 in an old wall become most attractive, their warmth 

 and dryness exactly suiting them. Alphonso Karr, in 

 his Tour round my Garden (in spite of its discursive- 

 ness, still one of the pleasantest of gardening books), 

 has a special chapter on an ' Old Wall ' ; but, while he 

 gives a few lines of praise to its vegetable beauties 

 1 in the crevices of its top extends an absolute crown of 

 yellow wallflowers and ferns, and at its foot vegetate 

 pellitory and nettles in all their beautiful green ' yet 

 his chief delight is in the animal life of the wall the 

 lizards, caterpillars, and spiders. 



But it is for the growth of alpines that the old 

 wall is especially useful. In many gardens it is found 



