LETTUCES. 553 



Leeks, like the Onion, require an open situation, and 

 that the ground be good, light, rich, and upon a dry 

 sub-soil. The first sowing may be about the middle of 

 February ; but the main crop ought to be sowed in the 

 middle or end of March. When the plants are three 

 or four inches high, they should be thinned out, leaving 

 them about nine inches apart ; or they may be planted 

 in deep drills, nine inches from plant to plant, and the 

 drills eighteen inches asunder. As the plants grow 

 stronger, the earth may be drawn to them so as at last 

 to fill the drills level, by which means the lower part of 

 the bulbs will become blanched, and much sweeter than 

 when it is more approaching to green. 



37. LETTUCES. 



Lactuca sativa, or Garden Lettuce, is well known 

 as furnishing, among its numerous varieties, the best 

 vegetable of the salad kind grown in the open garden. 

 The cultivated Lettuce will, if sown in the spring, pro- 

 duce ripe seeds in August or September ; and so far it 

 is strictly an annual : but if it be sown in autumn, it will 

 not produce seeds till the succeeding summer. It was 

 introduced or cultivated in 1562, but from what country 

 is unknown. 



The varieties are numerous ; but they may be arranged 

 in two divisions, viz. the upright, oblong, or Cos Let- 

 tuces ; and the round-headed, spreading, or Cabbage 

 Lettuces. 



Lettuces possess some medicinal properties; their 

 milky juice is a slight opiate, and occasionally produces 

 drowsiness ; eaten at night, they are, with some persons, 

 favourable to sleep ; but as they also possess laxative 

 qualities, they are apt, if eaten freely for several succes- 

 sive days, to derange the bowels, and to cause consider- 

 able pain and distention. 



