FOREIGN NOTICES. 



523 



two or three years cut in ; if vij^orous jrrowinsj sorts 

 these soon <jrevv into lari^e sin-eiulintr trees, shading' 

 a large space orsmunil. II', on the contrary, they 

 were delicate and rather tender, their shoots in a 

 few years conimenced to canker, and presently the 

 trees would be a mass of disease. Now pyramidal 

 pear trees on the quince stock, and apples on the 

 paradise stock, must not be stuck in in tliis manu'^r ; 

 they should be planted — and planted well, and have 

 summer pinching and winter root-pruning if inclined 

 to grow too vigorously ; surface dressing in autumn 

 and liquid manure in summer will also be found 

 highly advantageous. In short, they require cul- 

 ture ; in deep, rich, fertile soils, this surface dress- 

 ing and li()uid manuring may be dispensed with, but 

 in thin, drj' and light soils it is quite indispensable. 

 more particularly in thin soils resting on chalk ; in 

 such soils, even with the best culture, success will 

 not always attend the efforts of the cultivator ; but 

 I must honestly confess r.hat I have not yet seen 

 any failure. The following sorts of pears, I am 

 inclined to think, will succeed on the quince, even 

 on the most unfavorable soils ; they are planted 

 here in stiff, dark, adhesive clays — in light, calca- 

 reous, reddish sand — in sandy loam, and in a stiff, 

 red loam (such is the great variety of soils in my 

 nursery,) in all they succeed admirably, and give 

 abundance of fruit of large size and fine flavor : 

 Beurre Ananas, Beurre d'Amanlis, Beurre d'Arem- 

 berg and its congener Soldat Laboureur or Orphe- 

 line d'Enghien, Beurre Capiaumont, Beurre Diel, 

 Beurre Easter, Beurre Langelier, Bon Chretien 

 (William's.) Chaumontelle, Citron des Carmes, 

 Colmar, Crassane, Deliee de Hardenpont, D03'- 

 enne d'cte. Doyenne (white,) Duchesse d'Angou- 

 letne,Fortunce (Parmentier,) Glout Morceau,Gra- 

 tioli of Jersey, Louise Bonne of Jersey, Napoleon, 

 Passe Colmar, Saint Germain, Van Mons Leon le 

 Clerc. Vicar of Winkfield, Wilhelmine, &c. 



I must confess that I take great pleasure in the 

 culture of pyramidal trees — they are so productive, 

 so " gardenesque," so come-at-able, their fruit is so 

 easily gathered, the progress of the trees in all their 

 stages of growth is so under the eye of the cultiva- 

 tor that I feel assured it must make rapid progress, 

 in spite of such cavillers as '' Abdalonyinus" and 

 *■ Constant Reader." — Thomas Rivers. [Mr. Ri- 

 vers is perfectly right. Ed.] Gard. Chronicle. 



It is a well-known fact that the Diseases of 

 Plants, like those of animals, are occasionally epi- 

 demic, prevailing over the vegetation of large dis- 

 tricts ; and the question has often been asked — Are 

 they contagious or infectiont? — Are they propa- 

 gated by matter engendered in one individual and 

 communicated to another? We siiall endeavor to 

 answer these ([ucstions ; and we think that the con- 

 clusion must be arrived at, from the evidence be- 

 fore us. that the diseases of plants may be, like 

 those of animals, produced by contagion. 



Amonirst animals, diseases are engendered by 

 the application of organic matter in three forms : 

 1st, that of animals, as in the case of the itch-mite, 

 rot-worm, and the various forms of epi/.oa and en- 

 tozoa ; 2d, that of vegetables, as in the fungi of 

 scald-head, the confervaj of impetigo, and other 

 cutaneous diseases ; 3J, that of orgauic cells, whicli 



do not give evidences of the possession of a specific 

 animal or vegetable life, as in the case of small-pox, 

 measles, scarlet fever, typhus fever, &c.; and it is 

 these diseases which arc most frequently epidemic. 

 The same agents are caiiable of producing dis- 

 eases in vegetables. Tlic attacks of the aphis, the 

 scolytus, and other insects, are well known as pro- 

 ducing extensive destruction of herbs and trees over 

 large districts ; and the most frequent pestilences 

 that desolate the cultivated plants of our fields are 

 produced by various forms of fungi. The agency 

 of fungi is so great in producing blights, that some 

 writers have heen inclined to attribute all the dis- 

 eases of the vegetable kingdom, not produced by 

 insects, to this cause ; and the peculiar characters 

 which the cells of plants assume under disease have 

 been named as though they were so many species 

 of fungi. We arc indebted to Unger, a German 

 botanist, for having pointed out this error, and the 

 real source of the sujjposed forms of fungi. There 

 is not, however, any doubt that the greater number 

 of the mostdestructive pests of our fields — as those 

 known by the names of smut, brand, mildew, rust, 

 &c. — are produced by the introduction of the seeds 

 of fungi into the tissues of the affected plants. 

 With the history and nature of these, we are hap- 

 py to say we shall be able to make the readers of 

 the Gardeners^ Chronicle acquainted, through the 

 able pen of the Rev. Mr. Berkley. 



These cryptogamic diseases of plants must be 

 regarded as contagious, since they are produced by 

 the contact of one portion of organic matter with 

 another. But the diseased cells of a vegetable are 

 capable of communicating their diseased action to 

 healthy cells, just as tl.e cells from an animal af- 

 fected with small-pox are capable of giving that 

 disease to another. If a healthy plant of Cactus 

 be inoculated with some of the fluid from a plant 

 affected with moist gangrene, diseased action will 

 immediately commence, and extend more or less 

 rapidly according to the condition of the plant thus 

 inoculated ; and this is tiic case witii some other 

 forms of vegetable disease. The kind of action 

 thus established is analogous to that which occurs 

 when a small quantity of ferment is introduced into 

 a saccharine fluid, the consequence being the im- 

 partation of a new character to the particles of the 

 fluid, and an entire change in the relation of its 

 chemical constituents. In order that diseases may 

 be thus produced, it is not ncctssary that the con- 

 tagious matter be conveyed from one plant to ano- 

 ther in a tangible form, but the diseased cells may 

 be conveyed through the medium of the air, in the 

 same way as the sporules of fungi which produce 

 blights. 



In treating of contagious diseases or those pro- 

 duced by animals and plants, most writers have 

 paid almost exclusive attention to the agent pro- 

 ducing the disease, not taking into consideration 

 the condition of the plant attacked. In human be- 

 ings it is well known that only a small proportion of 

 persons exposed to the influence of contagion will 

 take the disease that it is calciflateil to produce. 

 Tiiere is, in fact, in both animals and plants a cor- 

 dition of the tissues of the individual, brought on by 

 circumstances, which favors the production of dis- 

 ease, and it is alono in our power over this condi- 



