288 THE NURSERY. [March. 



branches, yet hi order to obtain it more copiously, incisions are 

 made through the bark, by means of a sharp crooked instrument, 

 a slice of which is taken ott', about three inches in length and two 

 in breadth; they leave the wounds open, and by degrees the manna 

 runs out. The season thought to be most favourable for instituting 

 this process, is a little before the dog-days commence, when the 

 weather is dry and serene. The incisions are first made in the 

 lower part of the trunk, and repeated at the distance of an inch or 

 two from the former wound, still extendingthem upwards as far as 

 the branches, and confining them to one side of the tree, the other 

 side being reserved till the year following, when it undergoes the 

 same treatment. On making these, a thick white juice immediate- 

 ly begins to flow, which gradually hardens on the bark, and in the 

 course of eight days acquires the consistence and appearance in 

 which the manna is imported, when it is collected in baskets and 

 afterwards packed in large chests. Sometimes the manna flows in 

 such abundance from the incisions, that it runs upon the ground, 

 by which it becomes mixed with various impurities, unless pre- 

 vented, which is commonly attempted by interposing large concave 

 leaves, stones, chips of wood, &c. The business of collecting it, 

 generally terminates in those countries in September, when the 

 rainy season sets in. 



That manna is got in quantities on the leaves of trees, is an 

 opinion taken from the doctrine of the ancients, and received as in- 

 contestible without consulting nature; for all those who are em- 

 ployed in the gathering of it, know of none that comes from the 

 leaves; therefore, that with which the Israelites were so peculiarly 

 favoured, could only have been produced through miraculous 

 means, and is consequently out of the province of the naturalist. 

 The best manna is what exudes from the tree very slowly, and is 

 collected clean; this is always more dry, transparent, and pure, 

 for when it flows copiously it concretes into a coarse, brown, 

 unctuous mass. 



Methods of propagating Trees and Shrubs by Layers. 



There are few trees or shrubs, if any, but may be increased in 

 this way. The nursery gardeners who want to propagate large 

 quantities of various hardy kinds, of which they cannot easily pro- 

 cure seeds, and which by experience they do not find to grow 

 freely by cuttings, establish what they call stools, of the different 

 kinds intended to be propagated, particularly of the deciduous tribe, 

 and also some evergreens. For this purpose they plant in different 

 quarters, stout, healthy plants, at the distance of four or five feet 

 from one another every way, and head them down; these throw 

 out near the earth a number of young shoots, some of which may 

 be laid in the autumn or spring following; these stools, as they are 

 commonly called, continue for many years, always laying down 

 the shoots of the last season, and every year successively they pro- 

 duce abundance for the ensuing year's laying, still taking them ott" 

 either in autumn or spring as they become well rooted. The elm, 



