September 18, 1873. ] 



JOUKNAL OF HORTICULTURE AND COTTAQB GARDENER. 



211 



HOUSE SEWAGE A SAFE AND MOST VALUABLE 

 FERTILISER. 



UR contem-porary Medical Notes and Queries, 

 referring to our previous remarks on this 

 important subject, observes — "The well- 

 known experiments of De Saussure undoubt- 

 edly demonstrate that the roots of plants 

 are endowed with a certain power of se- 

 lection, under particular circumstances and 

 conditions ; but — and we speak with the 

 clear remembrance of the late Professor 

 Lindley's expressed views on this subject — 

 their import must not be overrated, and certainly do not 

 support the extravagant statement hazarded by The 

 JocRN.iL OF Horticulture, that ' the roots of plants 

 never absorb anything prejudicial to the plant's hcnltli.' 

 Many known facts in vegetable physiology are incon- 

 sistent with such an idea. If plants are absolutely in- 

 different to noxious matters brought into relation with 

 their absorbing surfaces ; if they absorb only what, and 

 BO much as, is good for them and compatible with their 

 highest condition of health (and this moderation is im- 

 plied in the statement that nothing ' prejudicial ' is ever 

 absorbedl, why cannot an unlimited supply of artificial 

 manure be given to plants without their being injured by 

 it ? If they wiU only absorb what they require, the 

 remainder, surely, wDl pass away and do no harm. But 

 is this the fact ? Of course we know that practically it 

 is not so, and that it is as necessary to regulate the 

 quantity, as it is to attend to the quality, of the manures 

 given to plants." 



The reply to this is obvious. Our observations apply 

 to the roots, not the surfaces. Cultivators have *' to re- 

 strict the quantity" of the manure applied to the roots 

 of some plants they cultivate, because, if fruit or seed is 

 the object to attain, and an excessive quantity of manure 

 is appUed, the plants become overlusuriant, and produce 

 an excess of leaves instead. If leaves or stems only are 

 required, as in the instances of Grass, Rhubarb, Aspa- 

 ragus, Cabbages, and some others, the manure applied 

 need not be so restricted. Now, that overluxuriance is 

 caused solely by the roots absorbing the manure and the 

 plants digesting and assimilating it. If the digestion was 

 deficient there would bo no overluxuriance. 



When we said that " the roots of plants never absorb 

 anything prejudicial to the plant's health," we were con- 

 sidering healthy roots growing in a suitable soil manured 

 with sewage or any other usual fertiliser, and then, we 

 repeat, the roots do not absorb anything prejudicial. If 

 the spongioles of the roots are paralysed or killed by an 

 injurious soil or the application of poisons, then we are 

 quite aware the roots lose the power of selection. We 

 published the following on that result some years ago. 



" Soils containing obnoxious ingredients are certain in- 

 troducers of disease and premature death. An excess of 

 oxide of iron — as when the roots of the Apple and Pear 

 get into an h-ony red gravelly subsoil— always causes 

 canker to supervene. In the neighbourhood of copper- 

 No. 651.— Vol. XXV., New Series. 



smelting furnaces, not only are cattle subjected to swollen 

 joints and other uuusnal tliseases, causing decrepitude 

 and death, but the plants also around are subject to 

 sudden visitations, to irregular growths, and to uu-., arned 

 destruction ; and a crop once vigorous will suddenly 

 wither as if swept over by a blast. There is no doubt 

 of this arising from the salts of copper which impregnate 

 the soil in-egularly as the winds may have borne them 

 sublimed from the furnaces, and the experiments of Seu- 

 nebier have shown that of all salts those of copper are 

 the most fatal to plants. 



" That they can be poisoned, and by many of those 

 substances, narcotic as well as corrosive, which are fatal 

 to animals, has been shown by the experiments of M. F. 

 Marcet. The metallic poisons being absorbed are con- 

 veyed to the different parts of the plant, and alter or 

 destroy its tissue. The vegetable poisons, such as opium, 

 strychnia, prussic acid, belladonna, alcohol, and oxalic acid, 

 which act fatally upon the nervous system of animals, also 

 cause the death of plants." 



Our contemporary next observes — "The Jouen.4L of 

 Horticulture disposes of oiu- reference to forced Rhubarb 

 having the flavour of horse dung, by saying, ' We know 

 both in that and in forced Sea- kale that it is occasioned 

 by the gases emitted by the fermenting dung ;' and that 

 ' the reek may be always removed by peeling off the 

 thinnest film of the epidermis.' Admitting this — which 

 we do only for the sake of the argument — surely it proves 

 our case ; for if a plant can absorb gas it can absorb 

 fluid, and neither could find their way into the epidermis 

 except through the cellular system of the plant. We 

 have ourselves smelt the sewage odour very strong from 

 the fresh-cut stalks of Cabbages ; and Mr. Smee, in the 

 Standard of September 5th, states that he has been in- 

 formed, 'by the medical officer of one of our largest 

 establishments, that ho has known Parsley to take up fho 

 flavour of gas tar so as to be useless ' — a remarkable in- 

 stance of the absorption of foreign matters by growing 

 plants, which, according to The Journal of Horticul- 

 ture, never takes place. 



" How can such facts be reconciled with the preter- 

 natural powers of absolute selection and rejection attri- 

 buted to plants by The Journal of Horticulture ?" 



The "facts" have no relation to the powers of "se- 

 lection and rejection " possessed by the roots of plants. 

 Those powers as possessed by the roots in relation to the 

 manure in the soil are all that wo ara contending for. 

 That the reek of fermenting dung or of gas tar will pene- 

 trate the epidermis of a plant, or of the human skin is 

 certain, but it is usually removeablo, as wo originally 

 stated, by washing. 



As to the odour of sewage being smelt in the fresh-cut 

 stalks of Cabbages, we venture to state that the same 

 odour would be perceived in any similarly luxuriant 

 Cabbages, whether that luxuriance was caused by sewage, 

 guano, or any other fertiliser. 



Medical Notes and Queries concludes, as is no inoro 

 than we expected, temperately and wisely by saying, 

 " The mere fact that iu very many cases sewage matter 



No. 1308.— Vol. L , Old Seeieb. 



