FOREIGN NOTICES. 



tion by the water they imbibe must pass witli it into tlio ct-ll cavities, and in tlioso cases 

 whore substances such as sllcx are taken up more freely by one i>laut than anotlier, llie 

 (lillieulty depends probably on mechanical laws which, at present, we are unable to aiii>re- 

 ciatc. If, liowever, the choice of the spongelets is limited, that of the stomates is still less 

 so, so that whatever gaseous matter may be contained in the atmosjihore will find a ready 

 admission to the inward parts of the plant. It is obvious, therefore, that as the exigencies 

 of plants are very different, and the same nutritive matter, or, rather, the same proportions 

 of it, will not suffice for the maintenance of health in all, even under ordinary circumstances, 

 disease may arise from a deficiency or redundancy of particular elements in the soil and 

 atmosphere. The salt steppes of Asia produce only such plants as delight in the particular 

 mineral which abounds in them, or are as able to tolerate it in such largo proportions. In 

 land, again, over-manured with guano or other animal matters, health, or even vitality, 

 cannot be maintained, where the proportion is such as to exceed greatly the wants of the 

 species. AYheat, for instance, will not flourish where there is a total absence of silex, nor 

 cabbages where the proportion of nitrogenous matter is very small. In some cases, indeed, 

 superfluous matter which could never pass off by the stomates, is stored uj) in the cavities 

 of the cells, as the crystals of oxalate of lime which form such a prominent and interesting 

 feature in the leaf cells of figs, hops, and many other plants, the rhaphides with which so 

 many vegetable cells are gorged, or the carbonate of lime in charads. There is no reason 

 to believe that these matters are deposited with a view to any ulterior use, as is the case 

 with the magazines of starch, &c., which are intended to perform important functions at some 

 future and often distant period. Other matters, however, may bo present in the soil or atmo- 

 sphere which are never requisite for health in any proportion, and which in themselves may 

 be destructive. Different as vegetables are from animals in a multitude of respects, there 

 are species which so closely resemble each other, that it is difiicult to say to which great 

 division of the organized world they really belong. Both these exhibit vital phenomena, 

 and we may presume, therefore, that the principle of life, however it may be modified, is 

 essentially the same in each. If proof, however, were wanting in other respects, the identity 

 of the effects produced by many vegetable and mineral poisons upon plants and animals 

 would alone be sufficient. ^Vliether we take the principal organic poisons, as opium, hydro- 

 cyanic acid, chloroform, -&c., or inorganic, as arsenic, hydrochloric acid, iodine, &c., we find 

 that the effect produced is essentially the same, in some cases affecting the functions, in 

 some the organic structure. Opium, hydrocyanic acid, chloroform, &c., paralyze or sus- 

 pend the functions of vegetables, precisely as they do those of animals without injuring the 

 delicate tissues ; while arsenic, lead, &c., more or less impair their structure. Nor is gase- 

 ous matter indifferent ; the comparative barrenness of fens, at least as regards the majority 

 of the natural order of plants, depends, in all probability, on the condition of sulphuretted 

 hydrogen ; the impure carburetted hydrogen of gasworks is notoriously injurious to trees, 

 as is also the emanation from certain chemical works, which reduce their immediate neigh- 

 borhood to a treeless wilderness. The mischief may, in many cases, be purely functional at 

 first, but the suspension of functions, especially if long continued or often repeated, except 

 where it is of the nature of sleep, is apt to induce active disease, or the destruction of 

 particular organs, which may in the end prove generally fatal. 



It is, however, curious what concentrated poison some vegetables are able to endure. 

 Moulds flourish in arsenical and other mineral solutions, which might have been supposed 

 utterly incapable of sustaining any vegetable. One species is the source of great annoyance 

 in electrotyping, as in the Map Office of the United States of Washington. The sulphate 

 of copper is deprived of its copper by the mould, which assimilates the sulphuric acid while 

 the copper is deposited as a tliin, metallic pellicle on its walls. A fungus again flour 

 in the water of tan-pits where no phtenogam could exist. 



