528 Queries and Answers. 



and the more necessary will be the stimulus of heat to enable it to overcome, 

 The exudation of gum in stone fruit is unattended, to the same extent, with 

 the cancerous morbid state of parts exhibited by the apple and pear ; but the 

 disease appears to exist also in the sap, and to be ramified through the 

 branches, in the same way as canker, as may be often seen on cutting in to 

 arrive at its source. The small unripened shoots appear most liable, as being 

 most tender. The bark and alburnum appear first to be infected in these young 

 shoots, especially in the peach ; the young wood of which, being delicate from 

 want of ripening, appears unable to stand the severity of spring, gets dis- 

 coloured in blotches, and gum begins to exude. It would appear here that 

 the disease arises from imperfectly ripened tissue getting injured by severity 

 of the weather, and affording a nidus for it. In other cases, however, the gum 

 begins to exude from parts to all appearance sound and perfect, as if caused 

 by a plethoric diseased state of the sap. It is probable that, as in the cancer 

 in the human body, which may be brought on from a wound neglected or a 

 diseased state of the blood or constitution, so likewise, in plants, the same 

 disease may be brought about by different causes ; as in the analogous fungoid 

 disease of mildew on the leaves, which, it appears, may be brought on by ex- 

 cess of moisture or excess of drought, producing a diseased state of the sto- 

 mata of the leaf, and a nidus for the fungus. — Sept. 21. 1842. 



Art. IV. Queries and Answers. 



Growing the Pine-Apple without Bottom Heat. (p. 432.) — In answer to your 

 correspondent " A Subscriber, Winton," relative to growing the pine-apple 

 without tan or other fermenting material, I beg leave to state that I lived 

 gardener to the late Mr. Knight, when he first commenced that mode of 

 growing pines ; but that, from a temporary illness, my doctor advised a change 

 of air, which prevented me then from carrying it out. The soil we chose 

 was from a river-side pasture. The house was well flued, but had no pits 

 for plunging or receiving the plants, °so that the pots stood isolated. I 

 found, as in the management of all heated houses for cultivation, that a 

 steady governance of the fires was essential ; and at the approach of a 

 hot sunny day they were allowed to subside, and rekindled again in time to 

 keep up a proper heat as the sun's influence subsided in the evening, &c. 

 A due regard to ventilation, to counteract the influence of the sun on the 

 glass, is also essential ; and I prefer houses so constructed as to afford ven- 

 tilation from all parts of the roof, as it prevents plants of all kinds from being 

 what is commonly called drawn. The pits now used with hot-water pipes, a 

 portion of which runs in gutters under the pits, afford a ready means of heat- 

 ing; and, if rightly applied, of bringing the fruit to perfection. If I can render 

 your correspondent any further service, I shall be happy to hear from him. — 

 F. Torbron. 3. Charles Place, Kensington Square, Kensington. 



Physospermum cornubiense Dec. (higicsticum cornubiense L.) — This rare 

 and very local plant has never been found in any other part of Britain than 

 about Bodmin, though it is said to be not unfrequent in the South of Europe 

 and in Greece. Dr. Withering says that cattle are so fond of the plant, that 

 they eat it down to the ground whenever they can get at it ; so that it 

 is usually found only in places where it is so protected by thorns and briars 

 as to be inaccessible to them. (Baxters British Flowering Plants, 475.) 

 Would this not be a desirable plant to sow along with clover and grasses in 

 artificial pastures ? — D. B. Brighton, August 3. 1842. 



