524 



FOREIGN NOTICES. 



tion that we can expect to control the visitation 

 and destruction of epidemic diseases. That such a 

 condition of plants exists is, we think, proved by the 

 fact that epidemic diseases arising from the attacks 

 of insects and fungi do not occur in the same dis- 

 . tricts in following years, although there can be no 

 doubt that there are more of the seeds of disease, 

 as the ova of insects, the seeds of fungi, &c., in the 

 vicinity of crops, in the year following an attack of 

 the disease, than in years either previous or subse- 

 quent to the attack. We think, then, that there is 

 reason to conclude that there are constantly in the 

 atmosphere germs which are capable of producing 

 disease in a plant, provided the plant gets into a 

 condition to be attacked. 



The circumstances that would produce such a 

 condition of a plant as to render it liable to the de- 

 velopment of epidemic diseases, are of a general 

 nature. The state of the atmosphere in relation to 

 moisture, the prevalence of unseasonable, hot or 

 cold weather, the amount of light, and probably the 

 electrical condition of the air and earth, are the 

 circumstances which act on plants generally, and 

 ■which may produce a state in which insects, fungi, 

 or organic germs, may generate disease. 



A more limited cause of predisposition to conta- 

 tious disease is the natural decay of a plant or parts 

 of a plant. Thus we find that the leaves are more 

 exposed to the attacks of fungi just before the fall 

 than at any other time. The trunk and branches 

 of a tree become most frequently gangrenous when 

 they have attained maturity. Soft fruits — as ap- 

 ples, pears, oranges, melons, grapes, &c., are more 

 exposed to the attacks of disease the riper they get. 

 Ripe fruit is already entering into a state of decay, 

 and this process is hastened by the introduction of 

 the seeds of fungi or the cells of diseased tissue. 



Can the epidemic diseases of plants be averted ? 

 We think in some cases they may, and in others 

 very much mitigated. We cannot control the sun 

 and the wind, nor prevent electrical accumulations 

 and escapes ; but we may act in anticipation of 

 their influence, and, if we cannot altogether pre- 

 vent the occurrence of epidemic diseases among 

 plants, we may do much to prevent their destruc- 

 tive consequences. Plants which have the most 

 perfect health will always withstand depressing 

 or exciting influences best, and the most carefully 

 cultivatedfarms and gardens will always be those 

 which, in the long run, will suffer least from blights 

 of any kind. It is not our object here to point out 

 the means of keeping plants in a healthy state ; but 

 we would say to farmers and gardeners — take all 

 care that your plants are healthy ; be careful of 

 stimulating them with heat, light, water, or ma- 

 nures ; be equally careful of depriving them of 

 a sufficient quantity of these things ; and guard 

 against poisoning them by noxious gases or impro- 

 per manures. The influence of particular varieties 

 of plants, and the age of them, in producing dis- 

 ease, we shall discuss in a separate article. L. E. 



Gard. Chronicle. 



Burnt Clay a Good Manure. — It has been 

 the custom here for some years, in spring, when 

 the operations of pruning, &c., are ended, instead 

 of suffering the rough branches to lie about, pre- 

 senting an untidy appearance, to collect them in a 



heap, and build a wall of turf round them in a semi- 

 circular form about three feet high. They are then 

 set fire to, and when about half burnt down, such 

 weeds and other rubbish as collect in exery gar- 

 den, and will not readily decompose, are thrown 

 on the top, and earth is gradually cast up as the 

 fire breaks through. 



During the first two or three days no ordinary 

 care is requisite to keep the pile on fire ; but after 

 this, if the fire is not ailoM'cd to break through and 

 thus expend itself, it will certainly spread through 

 tbewhoJe heap, and almost any amount of soil may 

 be burnt by still adding to the top. The soil we 

 burn is the stiflTest loam that can be found within 

 our limits, and is rather of a clayey nature ; also 

 turf from the sides of ditches and ponds, in itself 

 naturally sour and full of rank weeds. 



The clay thus burnt has been found beneficial in 

 every instance. In black garden mould, where 

 peach trees were disposed to sucker and canker, 

 despite of animal manures and drainage, two or 

 three annual dressings of burnt earth appear so to 

 have altered the soil that they now grow cleafi, 

 vigorous and healthy, are free from suckers, and 

 produce roots completely matted with fibre. The 

 like success has attended its application to other 

 fruit trees. 



During the summer of 1842, six beds of tea- 

 scented roses growing in an alluvial loam (the ad- 

 jacent fields are of the same soil, and grow large 

 crops of wheat and potatoes, but the particles of 

 soil run together after rain, and present a smooth 

 cemented surface) were manured with the follow- 

 ing substances, viz. — 1, bone-dust ; 2, burnt earth ; 

 3. nitrate of soda ; 4, guano ; 5, pigeon dung ; and 

 6, decomposed stable manure. The guano pro- 

 duced the earliest visible effects, causing a vigor- 

 ous growth, which continued through the season ; 

 the flowers, however, were not so abundant, and 

 the shoots did not ripen well, and were consequently 

 much cut with the frost. The bed manured with 

 burnt earth next forced itself into notice ; the plants 

 kept up a steadier rate of growth, producing abun- 

 dance of clean, well formed blossoms ; the wood 

 ripened well, and sustained no injurj' during win- 

 ter. The results of the other manures were not 

 remarkable — acting as gentle stimulants, the ni- 

 trate of soda and bone-dust least visibly so — al- 

 though they were applied in the quantities usually 

 recommended by the venders. 



From the fact of the beds of roses being all 

 planted at the same date, and their progress being 

 carefully watched, I would suggest the application 

 of burnt earth as an excellent manure for roses in 

 adhesive soils, as well as for fruit trees where dis- 

 posed to canker. Whether it acted by furthering 

 drainage, or by opening the soil to the fertilizing 

 influences of the atmosphere, or by fixing the am- 

 monia conveyed to the soil by rain, I do not pretend 

 to say, but its value is sufficiently apparent. I be- 

 lieve it is considered that the vegetable matter con- 

 tained in soils is destroyed by the act of burning ; 

 and I do not think the remains of the materials 

 used in combustion could exercise any extended in- 

 fluence, as the quantity compared with the earth 

 burned is so small, and the earth comes from the 

 heap burnt red and hard, and a great portion quite 



