Chap. 42.] INCISIONS MADE IN TEEES. 529 



Dog-star that irrigation is so particularly beneficial ; but even 

 then it ought not to be in excess, as the roots are apt to become 

 inebriated, and to receive injury therefrom. Care should be 

 taken, too, to proportion it to the age of the tree, young trees 

 being not so thirsty as older ones ; those too which require the 

 most water, are the ones that have been the most used to it. 

 On the other hand, plants which grow in a dry soil, require no 

 more moisture than is absolutely necessary to their existence. 



CHAP. 41. REMARKABLE FACTS CONNECTED WITH IRRIGATION. 



In the Fabian district, which belongs to the territory of 

 Sulmo 38 in Italy, where they are in the habit, also, of irrigating 

 the fields, the natural harshness of the wines makes it neces- 

 sary to water the vineyards ; it is a very singular thing, too, 

 that the water there kills all the weeds, while at the same 

 time it nourishes the corn, thus acting in place of the weeding- 

 hook. In the same district, too, at the winter solstice, and 

 more particularly when the snow is on the ground or frosts 

 prevail, they irrigate the land, a process which they call 

 " warming " the soil. This peculiarity, however, exists in the 

 water of one river 39 only, the cold of which in summer is 

 almost insupportable. 



CHAP. 42. (27.) INCISIONS MADE IN TREES. 



The proper remedies for charcoal-blight and mildew 40 will 

 be pointed out in the succeeding Book. 41 In the meantime, 

 however, we may here observe that among the remedies may 

 be placed that by scarification. 42 When the bark becomes 

 meagre and impoverished by disease, it is apt to shrink, and so 

 compress the vital parts of the tree to an excessive degree : 

 upon which, by means of a sharp pruning knife held with both 

 hands, incisions are made perpendicularly down the tree, and 

 a sort of looseness, as it were, imparted to the skin. It is a 



• 38 This was the native place of Ovid, who alludes to its cold streams, 

 Tristia, B. iv. El. x. 11. 3, 4 :— 



" Sulmo mini patria est, gelidis uberrimus undis, 

 Millia qui novies distat ab urbe decern." 

 Irrigation of the vine is still practised in the east, in Italy, and in Spain; 

 but it does not tend to improve the quality of the wine. 



39 The Sagrus, now the Sangro. 



40 " Uredo rubigo " and " uredo caries." 41 Cc. 45 and 70. ' 

 42 Still practised upon the cherry-tree. 



VOL. III. M M 



