Page:Encyclopædia Britannica, Ninth Edition, v. 17.djvu/71

MURRAIN 59 of citron- or rust-coloured fluid in various cavities, extravasations of blood and local congestions throughout the body, the blood in the vessels generally being very dark and tar -like. The most notable feature, however, in the majority of cases is the enormous enlargement of the spleen, which is engorged with blood to such an extent that it often ruptures, while its tissue is changed into a violet or black fluid mass. Inoculation. Anthrax in all its forms is an inoculable disease, transmission being surely and promptly effected by this means, and it may be conveyed to nearly all animals either by inoculation or through the digestive organs. The abraded skin is often the channel for the introduction of the bacilli ; and persons who handle diseased animals or their products as flesh, skin, wool, or hair often die from anthrax, which presents similar symptoms in mankind to those it exhibits in animals. The bacillus of anthrax, under certain con ditions, retains its vitality for a long time, and rapidly grows when it finds a suitable fluid in which to develop, its mode of multi plication being by scission and the formation of spores, and depend ing, to a great extent at least, on the presence of oxygen. The morbid action of the bacillus is indeed said to be due to its affinity for oxygen ; by depriving the red corpuscles of the blood of that most essential gas, it renders the vital fluid unfit to sustain life. Others assert that the fatal lesions are produced by the enormous number of bacilli blocking up the minute blood-vessels, especially of the lungs, and thus inducing asphyxia. It was by the cultivation of this micro-organism, or attenuation of the virus, that Pasteur has been enabled to produce a prophy lactic remedy for anthrax, which has already been demonstrated to be very effective ; and his discovery is likely to lead to most im portant results in procuring protective agents for other similar and fatal disorders in man and beast. Though his discovery was first made with regard to the cholera of fowls, a most destructive dis order which annually carries off great numbers of poultry, yet as applied to anthrax it has attracted most attention. This so-called attenuation or cultivation of the virus of the disease by Pasteur is effected by growing the bacillus in an albuminous fluid, the prefer ence being given to chicken-broth which has been previously steril ized by being raised to a temperature of 115 C. This broth is inoculated with a drop of anthrax blood which has been taken with antiseptic precautions from an animal about to die of the disease ; it is kept in pure air at a temperature of 42 to 43 C. ; at 45 the process of cultivation will not go on. After a certain time another quantity of broth is inoculated with a drop of the first, and kept under the same conditions ; and so this cultivation is carried on until a sufficient number of generations of the bacilli have been grown and the required degree of attenuation ensured. This is attained by attention to the temperature, allowing a certain inter val to elapse between each inoculation of the broth and the number of generations cultivated. The resulting "vaccine," as it has been improperly designated, when inoculated into the body of an animal liable to anthrax, confers immunity from the disease, if certain rules are attended to. Toussaint had, previous to Pasteur, attenuated the virus of anthrax by the action of heat ; and Chauveau has more recently corroborated by numerous experiments the value of Toussaint s method, demonstrating that, according to the degree of heat to which the virus is subjected, so its innocuousness when trans ferred to a healthy creature. The attenuation of heat, according to this method, is a safer and readier way to obtain a protective virus than Pasteur s broth cultivations. 2. Cattle-Plague or Rinderpest. The next disease is that which has, since the commencement of the last century, been generally described as " the murrain," but which is now better known as the " cattle-plague " or " rinderpest " (German). While anthrax is, with regard to species of animals attacked, the most universal of all diseases, being transmissible to nearly every living creature, including man kind, cattle-plague is limited to ruminants (oxen, sheep, goats, camels, buffaloes, yaks, deer, <fcc.). It is an Asiatic malady, and prevails frequently and with great severity in southern Russia (imported), Central Asia, Mongolia, China (south, west, and north), Cochin China, Burmah, Hindu stan, Persia, Ceylon, and the islands in the Indian and Malay Archipelagos. It is only known in Europe as an exotic and imported malady, it has not yet appeared on the American continent, in Australia, in New Zealand, or on the African continent, except in Egypt, into which it has been carried on several occasions, and where, owing to the absence of sanitary measures, it now prevails constantly. It is one of the most infectious and fatal diseases of ani mals a specific fever which runs its course so rapidly, and attacks such a large percentage of ruminants when it is introduced into a country, that from the earliest times it has excited terror and dismay. It has been noted that its irruptions into Europe in the earlier centuries of our era always coincided with invasions of barbarous tribes in the east of Europe ; and even at a later period the disease accompanied the events of war, when troops with their commissariat moved from the east towards the west, or cattle, when they were carried in the same direction. One of the earliest recorded irruptions of cattle-plague into western Europe occurred in the 5th century after the sanguinary invasion of the Huns under Attila, the expulsion of the Goths from Hungary, and the fierce internecine Avars of the whole Germanic population. The disease appears then to have been carried from Hungary through Austria to Dalmatia, while by Brabant it obtained access to the Low Countries, Picardy, and so on to the other provinces of France. In the curious poem De Mortibus Bovum written by St Severus, who lived at that period, the course and destructiveness of the disease are specially alluded to. Many invasions of Europe are described, and in several of these Britain was visited by it as in 809-810, 986-987, 1223-1225, 1513-1514, and notably in 1713, 1745, 1774, 1799. In 1865 and 1872 it was imported direct from Russia. Symptoms. Like some other general diseases, this does not offer any exclusive or pathognomonic symptoms, but is rather charac terized by a group of functional and anatomical alterations. An exact knowledge of its symptoms and necroscopical appearances is of the utmost importance, as its extension and consequent ravages can only be arrested through its timely recognition and the imme diate adoption of the necessary sanitary measures. Intense fever, diarrhoea or dysentery, croupous inflammation of the mucous mem branes in general, sometimes a cutaneous papular eruption, and great prostration mark the course of the affection, which is frequently most difficult to diagnose during life, especially if its presence is not suspected. Its introduction and mode of propagation can, in many instances, be ascertained only at a late period, and when great loss may already have been sustained. In the majority of cases the examination of the carcase of an animal which has died or been purposely killed is the best way to arrive at a correct dia gnosis. Indeed, this is practically the only certain means of con cluding as to the presence of the malady, as in different invasions, and even in different countries and different individuals during the same invasion, there are observed considerable A r ariations in the chief symptoms with regard to their intensity as well as in the secondary symptoms or epiphenomena. Among cattle indigenous to the regions in which this malady may be said to be enzootic the symptoms are often comparatively slight, and the mortality not great. So much is this the case that veterinary surgeons who can readily distinguish the disease when it affects the cattle of western Europe, can only with difficulty diagnose it in animals from Hungary, Bessarabia, Moldavia, or other countries where it is always more or less prevalent. In these the indications of fever are usually of brief duration, and signs of lassitude and debility are, in some instances, the only marks of the presence of this virulent disorder in animals which may, neverthe less, communicate the disease in its most deadly form to the cattle of other countries. Slight diarrhoea may also be present, and a cutaneous eruption accompanied by gastric disturbance, shedding of tears, and infrequent cough. In the more malignant form the fever runs very high, sometimes to 107 6 Fahr. , and all the char acteristic symptoms of the disorder are well marked, the lesions during life being observed-in the cheese-like deposits on the gums, the presence of petechise on the mucous membranes, discharges from the eyes, nose, and mouth, eruption on the skin, cough and laboured breathing, certain nervous phenomena, and dysenteric dejections. Death generally occurs in four or five days, the course of the disorder being more rapid with animals kept in stables than with those living in the open air, and in summer than in winter. After death the chief alterations are found in the digestive canal, and consist in evidence of inflammation of a more or less acute kind, with ulceration, extravasation of blood, gangrene, &c. The mem brane lining the air-passages offers similar alterations ; indeed, all the mucous membranes of the body appear to be involved, and the malady might almost be considered as a malignant infectious catarrhal fever. Protective inoculation has often been advocated and practised (particularly in Russia) for this disorder, but the advantages de rived have not been sufficient to compensate for the danger attend-