Retrospective Criticism. 493 



next summer, and, what is worse, their berries are neither good nor abun- 

 dant. But let us return to the first subject. 



On the Larian hills, in frosty nights, the wooden houses, or rather tents, 

 which enclose the lemon trees, are heated; but do you know how ? One, 

 two, or more fires are lighted, according to the size of the orangery (agru- 

 miera). The fuel is either wood or charcoal, and it is lighted, not in a 

 stove brought for the purpose, but on the floor of the orangery ; and thus 

 the plants are all more or less exposed to the smoke; which, being composed 

 of carbonic acid, acetic acid, carbon, water, and oil, and coming in contact 

 with the leaves, the cellular tissue of the fruit and the tender buds and 

 leaves are so disorganised by the action of these acids, that they fade and 

 fall off. 



Considerable profit is made by the cultivation of lemons on the Larian 

 hills. A single plant in the open air, well grown and well cultivated, 

 yields every year not less than 200 lemons. I have even seen one, the 

 trunk of which was a foot in diameter, which produced no less than 500 

 lemons every year. The lemons were sold at from 6s. to 10s. per hundred, 

 according to their size and the quantity of juice that they contained, and 

 according as the harvests on the shore of the Lake of Garda and in the 

 neighbourhood of Genoa were more or less abundant. Bitter oranges are 

 sold usually at about 2s. the hundred. The sweet at the same price as the 

 lemons, and sometimes less ; their sweetness being, as Mr. Spence observes, 

 less exquisite than that of the oranges of Malta. The use that is made of 

 the bitter oranges, in this part of Italy, is to make a pickle of them with 

 mustard. 



If the proprietors of the warmer declivities of the Larian hills understood 

 their interests better, they would raise plantations of bitter oranges, to use 

 them as stocks for grafting for the various species of lemons ; because the 

 lemon grafted on the bitter orange resists the cold better than in its natural 

 state: like the medlar of Japan (Eriobotryajaponicaiznrf/.), which, when 

 grafted on the whitethorn (Crataegus Oxyacantha L.), acquires additional 

 strength, and the true pistachio (Pistacia vera i.), which, when grafted on 

 the turpentine tree (Pistacia Zferebinthus L.), resists the cold of 8° Reaum. 

 ( 1 4° of Fahr.) ; while, if grown from the root, it dies at 5° (20f-° of Fahr.). 

 (See Sageret, Pomologie Physiologique, pp. 16, 17.) The constitution (so 

 to speak) of the lemons being strengthened in this manner, the tree may 

 be left standing in the open air, even in the depth of winter. The cul- 

 tivators of Nerva and of Monaco, in the Genoese territory, understand 

 this method of cultivating the lemon. Originally even they covered the 

 trees in winter with wooden sheds, and they raised the plants from the 

 root, propagating them either by seed or by layers (see Observations of an 

 Associate of the Academy of the Giorgofili Fiorentini, on the Cultivation of the 

 Agrumi, Florence, 1767); but, by dint of observation, they were aware that 

 it was necessary to try other means, and the result of their experience led 

 to the method of treating the orange and lemon trees which Mr. Spence 

 has pointed out to you. It is true that some of the fruit would probably 

 be frozen on the occurrence of a very severe winter : but this evil would 

 be trifling, compared to the advantages derived from the method of cul- 

 tivation practised by the Nervans and Monacoans ; and the loss sustained 

 might be diminished by gathering the frozen lemons immediately, and sub- 

 merging them in water at 0° Reaum. (32° Fahr.), by which, their tissues 

 thawing gradually, they would become as good as at first. 



Cultivation of the Pine-apple in the open Ground, in the North of Italy. 

 (p. 70.) — I can as yet say nothing satisfactory on the cultivation of the 

 pine-apple in the open ground. For two years I have sent some crowns 

 to a gardener on the Lake of Como, confiding to him the care of the 

 experiment ; and though these plants perished, I think it was from having 

 been watered too often and too much. Still, however, I am convinced 

 that, if treated carefully, and perhaps even if left to themselves, pines 



