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good family antecedents antecedents nor of personal health, live on through every untoward ordeal, physical and mental, and eventually attain old age. With them the " grasp upon life" is so strong, so tenacious, that they victoriously resist every influence, however unfavourable. As children, they may be neglected and badly fed; as men, they may be exposed to fatigue, to mental distress, to malaria and to disease in every shape; and yet through their strong inherent vital power, they resist every morbid influence, or, succumbing for a time, eventually rally and regain their footing on the shores of life.

Belonging to this class are the habitual drunkard, who yet attains old age; those who pass through threescore and ten years of disease and physical suffering; those who live long years in malarious, death-giving districts; the soldier who, if he escapes the enemy's ball, passes scathlessly through twenty campaigns; and the barrister who reaches the woolsack after half a century of mental toil and bodily inaction.

In all, the vital principle must have been exceptionally powerful, the hold upon life must have been exceptionally great, from the moment they drew their first breath. They are exceptions to the general rules which regulate health and life, and the exception has its explanation in this very intensity of the vital power which we recognize in its results, but can neither comprehend nor always foresee.

That such exceptions should occur is one of the most bountiful dispensations of Providence. Thus is the hope of long life given to all, even to the weak and the sickly. No human science or skill can unerringly estimate the inherent vital power of a fellow-being, however stricken by illness. If no organ indispensable to life is irretrievably compromised, the vitality of the sufferer may yet enable him to rally, to shake off disease, and to live to the allotted age of man.

FINIS.

R

APPENDIX I.

MINERAL ALIMENTS IN PLANTS-THE INFLUENCE OF HEAT IN ACCELERATING VEGETATION.

In the present work I have only devoted a few pages to the nutrition of plants, merely wishing to explain the chemical basis on which the nutrition of the animal world is based. To enter fully into the subject of plant nutrition would have taken a volume.

One of the most interesting features of modern research respecting the nutrition of plants is the discovery of the important part performed by mineral aliments. The old doctrine that decomposing vegetable substances, and the humus which is the result, were the all-important fertilizers of the soil, and, in a great measure, the origin of the carbon of plants, has been dethroned. Mineral aliments-represented by the nitrates resulting principally from the decomposition of animal substances, by the break-up and decay of rocks, in agriculture by guano and artificial manures, and by the oxygen and ammonia of the atmosphere—have been considered by many authors all but the sole origin of plant food, as stated at page 85. But these views are probably too one-sided, and the truth may, as is usually the case, be between the two theories.

Such is the view taken by Dr. Maxwell Masters in his recent edition of "Henfrey's Botany," a most valuable and interesting work. He therein states (p. 560)" it has been common in recent works to find the value of humous or carbonaceous matters in the soil estimated very low; they

have been regarded either as merely improving the (physically) absorbent power of soils, or as sources of carbonic acid, already sufficiently provided by the atmosphere. But the above observations (Mulder's researches), borne out by the experiments in turnip growing by Lawes and Gilbert, are in favour of a higher estimate of the value of decaying carbonaceous matters, and of regarding them as important constituents of farm-yard manures for certain purposes. Lawes and Gilbert found that stimulating nitrogenous manures in excess were rather detrimental to the growth of turnips, leaf formation going on at the expense of the roots; but this was counteracted in a great measure by supplying, with the nitrogenous manures, carbonaceous substances in considerable proportion."

It is a remarkable fact that many plants, like animals, have preferences as to the kinds of food they like; they have constitutions which require certain kinds of (mineral) food, and by which they are distinguished from other plants. Thus there are lime-loving plants which only thrive on lime soils, sea-side plants which only thrive in an atmosphere or soil containing sea salt (chlorine). Again, there are plants which only thrive in soils in which these two mineral elements are absent, or all but absent, such as those that principally occupy sandy soils at some distance from the sea.

The following remarks on the subject of mineral aliments in plants, and on the influence of heat in accelerating vegetation, were published in the Gardener's Chronicle, of August 21, 1875. I reproduce them here as bearing forcibly on this interesting subject.

In your issue of last Saturday (August 14) there are two questions raised, respecting which my experience of the Mediterranean shores and islands enables me to contribute a little information. 1st. The power of mineral detritus, or dust, to support vegetation, not only that of vines, but of cereals and of fruit trees, alluvial soil or humus being all but

absent. 2nd. The comparative influence of temperature in leaf development in southern and northern climates.

The entire north shore of the Mediterranean, from Gibraltar to the Dardanelles, with the exception of the mouths of rivers, may be said to be a mass of rocky mountains, principally calcareous, sometimes schistic. The southern flanks of these mountains or rocks are generally more or less precipitous, and burnt as they are by a southern sun, with a five or six months' summer drought, present but a scanty vegetation, pretty nearly everywhere of the same character-Borage, Thyme, Juniper, Euphorbia, Taraxacum, Cistus, Lavender, Rosemary, Mediterranean Heath, Lentiscus, Maritime Pine, Aleppo Pine, etc.; and, where cultivated, Olive, Orange, Lemon, Almond, Apricot, Peach, Vine, Opuntia, etc.

The wild plants and trees above-named cover the rocks sparsely, so as often to be scarcely perceptible at a distance, but grow healthily, if not vigorously. If their roots are traced they will generally be found to have entered a crevice, or fault in the rock. In calcareous rocks these crevices are very common on the surface. If such rocks are broken or blasted they will generally be found to present them in great numbers, and the roots of the plants growing on the surface will be found therein contained; often, but not always, surrounded by a little vegetable soil, the result of the decay of similar roots, their predecessors for countless ages. These plants and trees subsist clearly, in a great measure, on atmospheric and mineral food; for they get scarcely any other.

The cultivated plants and trees being all grown for the fruit they produce, although in a congenial climate, require man's assistance to produce it of good quality, and this is the way in which such assistance is given. Terraces or shelves are formed by the pickaxe, hammer, or by blasting, on the side of the mountain. These terraces are filled with broken and

powdered stones. A little road-dust or a little vegetable soil, if it can be found, is scattered on the stones; a hole is

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