Whether this epizooty totally ceased within ten years, or, indeed, whether it has ever been completely extirpa ted, may be the subject of dispute. Perhaps the renewal of epidemics is judged to be such, only because observa tions are not sufficiently extensive to prove that they are always subsisting. In the course of the year 1746, a new remedy, inoculation, had been attempted at Brunswick, and in an epizooty which appeared in Holland during 1755, the same remedy was repeated, though with little success, and recommended in Britain by Dr Layard, in the year 1757. The distemper in the latter country was considered absolutely similar to the small-pox ; and the infection was said to have been brought from Holland by two white calves of a favourite breed, or by two skins of diseased animals. Whatever was the case, many cattle perished of it.
Different epizooties appeared about the same time among the cattle, horses, and reindeer of France, Aus tria, Finland, and Lapland. Swine, dogs, and even poul try, are said to have been attacked by it. Russia did not escape ; and, if we can credit the relations given, the ma lady was propagated by the skin of an infected bear, even to the destruction of mankind. These epizooties were either perpetuated or renewed during the years imme diately subsequent, and, if possible, raged more exten sively among the various genera of animals. The horses of Switzerland, the cattle of Other countries, sheep, and particularly lambs, were swept away in thousands. In 1764, dogs were attacked throughout France, poultry in Spain, and the rest of the feathered tribes all over Eu rope. The milk of infected cows spread the contagion ; for those animals supplied with it were covered with pustules ; and people who suffered in the same manner experienced great difficulty of deglutition, and burning heat in the throat.
For some years, about this period, an epizooty raged among the black cattle of Holland. It first manifested itself in the province of Groningen, especially in the vil lage of Haren, and spreading insensibly, carried off the whole cattle belonging to a neighbouring district. Its at tack was announced all at once by the animal becoming dull, and rejecting drink. Fever and shivering, attended by a general prostration of strength, followed; the ears and horns grew cold ; a cough became unremitting ; a purulent matter was discharged from the nose, and an ichorous fluid flowed from the eyes. The hide was puffed up, and a crackling, like that of parchment, was heard on pressure. Some were attacked by diarrhoea, others by constipation from the fourth to the sixth day of the disease, and they died from the second to the eleventh day after its commencement. The blood of the animals then proved thin ; the intestines inflamed and putrid ; the lungs gangrenous ; the gall bladder always greatly enlarged ; and many fasciolx were in the liver. The symptoms were generally the same ; and
Camper, who strictly watched the appearance, progress, and issue of the malady, pronounced it a contagious pu trid fever. Animals once attacked were never liable to its recurrence, or at least very rarely ; hence Camper. from that and other circumstances, concluded, that, to repress it, four principal objects were to be kept in view. 1. To endeavour to prevent the malady, and abate its virulence. 2. To preserve the fluids from corruption. 3. To preserve the strength of the animal. 4. To cleanse the intestines immediately on the appearance of the dis ease. It is unnecessary to enter on any detail concern ing these different principles ; but respecting the first, in Camper's opinion, there was no means of guarding against contagion, but by excluding diseased animals., and all substances by which infection might be commu nicated. He also conceived that inoculation was the most probable method of averting the malignity of the distemper. He was not discouraged by the doubtful issue of former experiments, and even repeated them on a more extensive scale. His first essays, which he did not consider particularly successful, saved 46 out of 112 infected animals: again, 46 were preserved out of 92 ; and, if cows were not far advanced in gestation, three-fourths survived the malady by inoculation. Not withstanding this naturalist's anxiety to proceed still more extensively, it was found impracticable to persuade the proprietors of the animals of the expediency of in tentional infection, whence the system of inoculation was soon brought to a close. It has nevertheless been successfully practised elsewhere, particularly in Den mark ; and in the first three years of the experiment, less than a sixth part of the infected cattle was lost. Strong prejudices, perhaps they can scarcely be called imprudent, were opposed to the same proposal in Eng land, when an inoculator applied to the privy council for permission to carry the variolous matter from Hamp shire into other counties. It was then remarked, that the introduction of a disease where it did not exist, might spread by contagion beyond the power of experi ment to cure, and that it was already known the malady might be extirpated by killing the cattle. Camper es tablished several important points; such as, that the epizooty imparted by inoculation, was exactly similar to that communicated by natural infection ; that it was of a much milder nature ; as also, that animals infected in this way, resisted both natural contagion and the conse quences of inoculation. This malady proved extremely destructive in Holland ; for it appeared, that of 286,647 animals attacked, not fewer than 208,354 died.