with the the evil of extraordinary root extension and unnatural diminution of leaves, (or the evaporating organs,) by excessive pruning. We know that in the vine, as in other plants, the growth of the root and its branches keeps pace extension of the stem. As the latter shoots upwards and expands its leaves, the former grow outward, absorbing moisture to supply the evaporation into the air. The older the vines the greater must the root expansion have become, and the more numerous the rootlets occupied in absorption; but the annual pruning at one fell stroke destroys the equilibrium which nature had endeavored to establish, and the leaves and fruit of the aged pruned vine are rendered liable to engorgement and suffocation with excess of moisture or of sap. GENERAL REMARKS ON MILDEW. Frequent reference has been made to mildew, and some explanation of the meaning of the term and notice of our present knowledge of this evil may be here in place. bave Fungi are an extensive family of cryptogamous plants, generally known as mushrooms, toad-stools, rust, smut, mould, mildews, etc. They are generally parasitic, or grow upon and derive their nourishment either entirely or in part from the substances they infest. They are found wherever there is decaying vegetation upon which to feed, and sometimes prey upon living tissues. Nothing of vegetable origin is free from their ravages, when exposed to influences favor able to their growth. They are found also on animal dejections, on insects, whose death they cause, on the human skin, and even on bare stones, on iron but a few hours removed from the forge, and on acid chemical solutions. Our house-flies are often destroyed by a mould which, growing between the seg ments of their bodies, produces the white rings thereon, as many may seen. Some cutaneous disorders are the result of the operations of these vege table parasites. Oidium albicans forms the disease called aptha cous membrane on the tongues of infants, penetrating so deeply deeply as to be irre movable by art. It is found also in the nose, the wind-pipe, stomach and intes Fungi are an attendant of diphtheria, and are present in cholera vomitus as well as in yellow fever. Other parasitos not much dissimilar abound in the scalp, causing diseases, others on the teeth, some on the respiratory organs of birds, in their brains and eggs, and they have even been observed in the midst of the human eye. Fish are often covered with them; the silk-worm has been destroyed by the Botrytis bassiana, and the "potato-rot" is now ascribed to the Botrytis infestans, both forms of fungous growth. tines.* on the mu * Dr. Laycock and others regard diphtheria as due to the Ordium albicans whose sporules and mycelium have been found on the mucous membrane of the mouth, fauces, etc. Diph theria is most common in the foul districts of France and England, and is attributed to the action of putrid effluvia on the fauces, especially the foul air of sewers and cesspools, which offer highly favorable conditions for the propagation of fungi. Vitray and Desmartis are of opinion that there is no distinction between the Oidium albicans and Ordium Tuckeri, the former causing the diphtheria, the latter the European vine mildew. A connexion between the appearance of the European vine-mildew and the various forms of epidemic laryngeal maladies has been observed, which strengthens this presumption, the spread of the former having been followed by that of the latter. Rev. Mr. Berkeley, one of the highest authorities on fungi, says that the mould so extremely common in England on pears, apples, and other fruits in autumn, and frequently, while yet hanging on the tree, is the Oidium fructigenum, which is another species of the genus to which that causing diphtheria belongs. He also asserts that the Isabella has never suffered from the mildew when grown in Europe, though the Oidium Tuckeri destroyed the European vines generally, from England to Madeira. Many of these conclusions we believe to be unwarranted assumptions, so much remains to be learned respecting the classification of fungi. The vine-mildew of our native vines is not the Ordium Tuckeri, and even this is now shown to be but a barren form of another genus, known as Erysiphe. Prof. J. H. Salisbury has shown that the cause of "fever and ague" is no longer involved in mystery. He has not only detected, figured and described with minute accuracy the species of fungus which produces this disease, but has propagated and cultivated the plant within doors to an extent sufficient to contaminate the atmosphere of the apartment and induce attacks of fever among its inmates. His labors also demonstrate that measles are of cryptogamous or fungous growth. (See Ohio Agricultural Report, for 1863, and American Journal of Medical Sciences, January, 1866.) These microscopic vegetable growths are probably also the predisposing cause of variola and small-pox, of the cholera and the rinderpest, and of the plague of olden time. Their dwelling-place is as universal as their growth is simple; the air we breathe contains them, and the winds waft their seminal spores from pole to pole. They attack the housekeeper's bread and cheese, her preserves, her paste, her ink and her linen.t Her yeast consists of a living organism which is among the lowest of the fungi, and there seems to be abundant experimental proof that the various kinds of fermentations, acetous, vinous, lactic, &c., are due to different kinds of organisms, or different generations of the same species, all of which are fungi. Their attacks are not confined to the seeming dead forms of matter, but they play havoc with our fruits, (as the peach, the pear, the plum,) and attack remorselessly the foreign gooseberry, and both the foreign and the native vine and grape. No class of organized structures is so little known, and the study of fungi is among the most recondite of pursuits. This arises from their microscopic character, their strange growths, the variety of forms through which they pass, baffling the researches of the closest observers. But enough is now known to show that they are perfect plants, growing from and producing bodies analogous to seeds; that a single plant produces millions of spores, or reproductive bodies, which are so small that they float upon the air scarcely affected by gravity; that they remain for an indefinite period inert, and are called into sudden vitality by atmospheric changes favorable to their germination; and that their sudden appearance can be readily explained to be due to natural causes, obscure only because unseen. They have been traced through their changes from the infinitesimally small spore to the perfect plant; hence they are not the result of spontaneous generation, as has been imagined by some, though it would seem scarcely possible for any intelligent person to conceive such an origin. The earliest vegetation of these obscure creations is a prolongation of the membrane of the spores or seminal dust, and not properly seeds, because merely individual cells. From these proceeds a delicate, minute, webby growth called the mycelium, the true vegetation of the plant, and from this arises the reproductive bodies on which are formed the spores for future growth. It is this mycelium or close-growing mould which penetrates and destroys the object on which it is parasitic, or has fastened itself. Its fibres are so minute as to readily traverse the tissue or substance of the plant, and even the pores of solid wood, as may be seen in the "dry rot." The spores produced from this mycelium are 80 minute as to appear like a cloud of impalpable dust. And when we consider how readily germs so minute and almost omnipresent, may be drawn up with the fluids which enter through the roots, or may be received directly through the breathing pores or plants, and remember that their office is to prey upon vegetable substances which are decaying, or have received a check through untoward at The theory of the "cryptogamous origin of malarious and epidemic fevers" was broached by Dr. John K. Mitchell, of Philadelphia, upwards of twenty years ago, as will be seen on consulting his lectures bearing the above title, and republished in five essays in 1859. These lectures abound in facts of interest and value. Dr. Forry relates that, in Florida, he had known fungi to spring up in a night and to incorporate themselves with a woollen garment so inextricably as to render separation impracticable. mospheric influences, we may be prepared to comprehend how they may suddenly appear over widely distant regions, and commit ravages so appalling. So little is really known of the relations which these plants bear to each other, the transformations they undergo, or the seeming transmigrations from one form to another, under change of conditions, &c., that a wide field of inquiry is here open to the young and assiduous microscopist. When we state that the fungus, producing fermentation in yeast, (or the true yeast itself,) will grow upon the diseased scalp of a scrofulous patient, take root, and exist for years without check by the medical treatment attempted; that the fungus from the "ringworm," a disease of the skin, has been successfully used to produce fermentation (and that nearly as briskly as healthy yeast) when added to a barley wort;* and finally, that forms of fungi considered distinct species cannot be distinguished from each other, or from yeast, but that their differences seem to be entirely dependent upon the kind of plant, or the diseased animal tissue on which the spores may chance to alight, we may well believe that much remains to be learned be fore the naturalist will be prepared to fix the place in his system of even the common mildew of our vines and grapes. Accordingly, the best informed my cologists have not determined to what undoubted genus our vine mildew belongs. Minds of the first class are, however, zealously engaged at present in the eluci dation of the structure, and in determining the laws which govern these minute and mysterious organisms. To discover the causes of mildew and rot has exercised the ingenuity of many inquirers. Some believe they have certainly found them in deep trenching, abounding humus, and retentive soils and sub-soils; all of which are highly injurious in seasons of great atmospheric humidity, and conducive to the production of the "rot." Others assume that the cause of the rot is also the cause of the mildew, because they appear about the same time; but we believe without good reason. Both these evils no doubt arise from some derangement affecting the normal functions of the vine-some departure from the conditions of heat and moisture, either in the air or in the soil, which are absolutely demanded for its healthy growth and the maturation of the fruit. This must be self-evident, while it should also be equally clear that these conditions of temperatures and humidity, abnormal or excessive, are aggravated or rendered more injurious by the qualities of soil or position-by some esteemed the direct and specific cause of these evils. A cause for the sudden and wide-spread advent of the mildew on our grape leaves and fruit must be found as wide in its operation as is the resultant evil consequence; and must, therefore, be climatic, and climatic only. The outline sketch of the meteorological changes which preceded and accompanied this evil, and the freedom from its extreme effects in localities near wide waters, where these excessive changes of temperature and dryness were especially modified, point to the atmosphere and its fluctuating conditions as the controlling cause of the derangement which prepares for the growth of the fungi spores. case. Some may still believe we have not found this cause in the cold nights resulting from extreme dryness, and the hot days following immediately thereafter, because the leaves of the vine were not frozen, nor even appeared to be injured in every In reply, we may say that the extreme low temperatures, followed by extreme high heats, accompanied by excessive dryness, are all conditions highly favorable to the development of the spores of the mildew, which feed upon dis organized tissues; and that freezing is not necessary to prepare for decay, may be learned from the following passage from our highest authority in physiological botany. A. de Candolle asserts, that "cold does not kill vegetation by a me chanical action proceeding from congelation of the fluids of vegetables, as some naturalists pretend. We recognize rather a physiological action in this change, for the vitality of the tissue is destroyed by a certain degree of cold, followed by * Journal of Microscopic Science, January 7, 1866. a certain degree of heat, according to the peculiar nature of the plant. In the same manner as the gangrene which follows the thawing of a frozen part causes the death of an animal tissue, so the change or putrefaction which follows on rapid thawing will be the principal cause of the death of the vegetable tissue. This is illustrated by the immediate death of hot-house plants when exposed to a temperature several degrees above freezing." Herein lies the philosophy of the change in the tissue of the leaves exposed to intense radiation through dry air at night, followed by intense heats at mid-day in the same drying atmosphere. The minute vessels are ruptured or dried up, and disorganized, so that decay is induced, and the ever-present spores of the fungus at once find a nidus in the decaying matter, for the removal of which they were created, take root, penetrate the leaves, or enwrap the berries, feeding upon the former and choking the latter, and destroying the remaining vitality of both by their rapid expansion and fatal folds. OZONE AND THE VINE MILDEW. There are other atmospheric conditions, resultants of extreme dryness, or extreme humidity, or unusual cold, which indirectly affect the vine, and aid the development of fungous growth. It has been suggested that the relative amount of ozone in the air, which may be a peculiar form of oxygen, (or a component of this gas, if it be compound,) may exert an influence in promoting or preventing the appearance of the fungi on our vines and on other plants Though much remains to be learned respecting the development and character of this mysterious agent, we already know the conditions most favorable to its production, as well as those inimical to its appearance, or at least to the active exhibition of its energies. We know that chemical action increases with increase of heat and diminishes with reduction of temperature, and that ozone is less prevalent in the air during frosty weather. Moisture, to a certain amount, is favorable to chemical action, while an excess is detrimental thereto; and though there is less ozone in the air when very dry, there is still less when it is very moist-a certain degree of humidity being favorable to its development and existence. Dr. Smallwood, the meteorologist of Montreal, asserts that ozone is never present in dry air, and that the psychrometer will indicate its presence or absence. He adds, that east and south winds are ozonic at Montreal, and that northeast winds from off the land are not ozonic; also that westerly and northerly winds do not bear ozone with them, though sea breezes with moisture are strongly ozonic. These conditions are, however, modified in other latitudes, as we have observed repeatedly that winds from the N., NE., S.E., and S. W., may be strongly ozonic at our station. Dr. Smallwood also has shown that there is a connexion between the amount of ozone in the air and the health of a district. Thus, during the prevalence of cholera the amount of ozone is least, and the humidity was at the same time diminished. Dr. Moffatt has concluded, from the results of a large number of experiments in England, that ozone plays an important part in controlling or preventing epidemics, generally by removing the cause prevailing in the infected air of a district. Finally, C. Kosman has ascertained at Strasburg, France, that the green portions of all plants exhale ozone, the result of the chemical changes going on at the surface, or in the vessels of the leaf. The origin of infectious diseases prevailing over wide districts has, in some instances, been shown to be due to the presence of minute fungi, or rather to their germs or spores, which are ever ready to take hold and grow in favorable positions and conditions; and we know that our grape-vines are sufferers from causes having many points of analogy with the above. Now, when we consider that the appearance of mildew is invariably preceded by sudden changes in the atmospheric moisture or dryness, heat and cold; that excessively moist air as well as excessively dry air are both unfavorable to the presence of ozone, which acts so energetically in the destruction of fungi; that plants, when in health, give out ozone, and thus protect themselves from the devouring enemy ever ready to pounce upon the unprotected organism, we need not wonder that, during our oppressively moist days and unseasonably cold nights, the chemical changes connected with (or themselves the sources of) the vitality of the plant should be subdued or oppressed, the quantity of ozone in the air and on the leaf be diminished, and the torpid condition of the leaf render it an easy prey to the invisible but omnipresent enemy, and universal mildew be the result. THE CATTLE PLAGUE IN EUROPE. BY J. R. DODge, of the DEPARTMENT OF AGRICULTURE. The years 1865-'6 will be memorable in the annals of British farm stock. Long will farmers of the island kingdom painfully recur to recent scenes of suffering and pecuniary loss, in yard and field, in shed and byre, when medica tion seemed worthless and recovery impossible. Three millions of pounds sterling, or fifteen millions of dollars, may be a moderate estimate of the diminu tion of the meat supply and stock of the farm; but the indirect money losses flowing from the visitation in the cost of treatment and care, in diminished profits of pasturage, reduction of the aggregate stock of farm-yard derangement of crop rotations, failures of farmers of moderate resources, increase in prices of meat, and other items of pecuniary damage, are not at present calculable. manures, The disease has distinctive characterestics, but they are so numerous that a confusion of names for it has arisen in different countries, at different times. Formerly it was known only as a murrain, a general designation for fatal diseases among cattle. In Germany, where its visits have often excited alarm and elicited medical inquiry, it has been known by a variety of hard words, given in accordance with prevalent theories of its nature, one of them signifying an impaction of the third stomach; others having reference to the condition of the liver; others meaning gastric fever, and malignant dysenteric fever. In France it is called Peste, and Le Typhus contagieux des bêtes bovines. Sometimes it is known as the Siberian Cattle Plague, which is liable to be confounded with the Siberian Boil Plague-an enzootic rather than an epizootic disease. Gamgee formerly called it Contagious Typhoid Plague. Typhus Boum Contagiosus s common upon the continent. In Great Britain it is the Cattle Plague. It is in all these localities the same disease, having the same symptoms, and attended with similar fatality. HISTORY OF THE DISEASE. It is deemed probable by European veterinary authorities that rarely has a period of fifty years elapsed without a visitation of some deadly cattle disease, Homer's Iliad, Virgil's Georgies, Columella, and several ancient agricultural writers, attest the correctness of such a view. The history of six hundred years past, more familiarly known, is full of references to these murrains, generally for lowing in the wake of large armies, and spreading desolation among farm herds, These outbreaks were not always the present rinderpest. The Black Death, commencing in 1347, attacked men, horses, cattle, deer, bears, wolves, hareš, |