"The part of the estate to which the sheep unfortunately had access, where the predisposing causes of disease prevailed, was an orchard, having a gradual slope of about three quarters of a mile in extent, from the high ground to the bed of the river, ranging about east and west; the hills on each side being constituted of argillaceous strata of laminated slate, which, although having an angle of inclination favoring drainage on the slopes, yet in the valleys often became flat or horizontal, and on which also accumulated the clays, and masses of rock, in detached blocks, often to the depth of twenty feet—a state of things which gives the valley surface and soil a very rugged and unequal outline; the whole, at the same time, offering the greatest obstruction to regular drainage.
"These are spots selected for orchard draining in England; the truth being lost sight of, that surfaces and soil for apple-tree growth require the most perfect admixture with atmospheric elements, and the freest outlet for the otherwise accumulating moisture, to prevent dampness and acidity, the result of the shade of the tree itself, produced by the fall of the leaf.
"On this estate these things had never been dreamt of before planting the orchards. The apple-tree, in short, as soon as its branches and leaves spread with the morbid growth of a dozen years, aids itself in the destructive process; the soil becomes yearly more poisonous, the roots soon decay, and the tree falls to one side, as we witness daily, while the herbage beneath and around becomes daily more unfit to sustain animal life. Numerous forms of poisonous fungi, microscopic and otherwise, are here at home, and nourished by the carburetted and other forms of hydrogen gas hourly engendered and saturating the soil; while on the dampest spots the less noxious portions of such hydrates are assimilated by the mint plant in the shape of oil; and which disputes with sour, poisonous, and blossomless grasses for the occupancy of the surface, mingled with the still more noxious straggling forms of the ethusa, occasionally the angelica, vison, conium, &c.
"This state of things, brought into existence by this wretched and barbarous mode of planting orchard valleys, usually reaches its consummation in about thirty years, and sometimes much less, as in the valley under notice. Thus it is that such spots, often the richest in capabilities on the estate, (the deep soil being the waste and spoil of the higher ground and slopes,) become a bane to every form of useful vegetation; and, at the same time, are a hotbed of luxuriance to every thing that is poisonous, destructive, and deleterious to almost every form of animal life. And such an animal as the sheep, while feeding among such herbage, would inhale a sufficiency of noxious gases, especially in summer, through the nostrils alone, to produce disease even in a few hours, though the herbage devoured should lie harmless in the stomach. But with regard to the sheep in the present case, we fear they had no choice in the matter, and were driven by hunger to feed, being shut into these orchards; and thus not only ate the poisoned grasses, but with every mouthful swallowed a portion of the water-engendering mint, the acrid crowfoot, ranunculus leaves, &c., surrounding every blade of grass; while the other essential elements of vegetable poison, the most virulent forms of agarici and their spawn, with other destructive fungi, were swallowed as a sauce to the whole. This fearful state of things, to which sheep had access, soon manifested its results; for although a hog or a badger might here fatten, yet to an animal so susceptible to atmospheric influences, unwholesome, undrained land, &c., as the sheep, the organization forbids the assimilation of such food; and although a process of digestion goes on, yet its hydrous results (if we may use such a term) not only overcharge the blood with serum, but, through unnatural channels, cause effusion into the chest, heart, veins, &c., when its effects are soon manifested in sudden and quick dissolution, being found dead in the attitude of sleep."
It is probable that the gases which arose from this imperfectly drained estate played their part in the work of destruction; not only by coming in immediate contact with the blood through the medium of the air-cells in the lungs, but by mixing with the food in the process of digestion. This may appear a new idea to those who have never given the subject a thought; yet it is no less true. During the mastication of food, the saliva possesses the remarkable property of enclosing air within its globules. Professor Liebig tells us that "the saliva encloses air in the shape of froth, in a far higher degree than even soap-suds. This air, by means of the saliva, reaches the stomach with the food, and there its oxygen enters into combination, while its nitrogen is given out through the skin and lungs." This applies to pure air. Now, suppose the sheep are feeding in pastures notorious for giving out noxious gases, and at the same time the function of the skin or lungs is impaired; instead of the "nitrogen" or noxious gases being set free, they will accumulate in the alimentary canal and cellular tissues, to the certain destruction of the living integrity. Prof. L. further informs us that "the longer digestion continues,—that is, the greater resistance offered to the solvent action by the food,—the more saliva, and consequently the more air, enter the stomach."
STAGGERS.
This disease is known to have its origin in functional derangement of the stomach; and owing to the sympathy that exists between the brain and the latter, derangements are often overlooked, until they manifest themselves by the animal's appearing dull and stupid, and separating itself from the rest of the flock. An animal attacked with staggers is observed to go round in a giddy manner; the optic nerve becomes paralyzed, and the animal often appears blind. It sometimes continues to feed well until it dies.
Indications of Cure.—First, to remove the cause. If it exist in a too generous supply of food, reduce the quantity. If, on the other hand, the animal be in poor condition, a generous supply of nutritious food must be allowed.