492 



On the Sheep'Pox\ 



so strongly as to lose part of their ears, yet not one of them died. 

 The inoculation plan was equally successful with many of my 

 tenants^ -who followed my example and urgent advice ; but in 

 another village on this estate, where the peasants, from a dislike to 

 novelties, suffered the contagion to take its course, there was not, 

 to the best of my recollection, a single sheep left alive. 



For the sake of distinctness, I shall now proceed to state the 

 mode, the most favourable time for, and the general effects of, 

 inoculation, when it has been effectively operated, as well as some 

 rules to be observed in the treatment of the inoculated animals. 



Mode of Inoculation. — Where yearly inoculation is practised, it 

 is customary to reserve a stock of inoculating materials from one 

 year to another, always taking particular care to obtain it from 

 individuals which have the disease in a mild form, and which are 

 apparently otherwise in a sound state of health. In cases of 

 sudden emergency, arising from already existing or dreaded in- 

 fection, the inoculating virus must of course be procured with all 

 possible dispatch, yet with as careful selection as to mildness of 

 form as circumstances will permit. If the inoculation be only 

 precaulionar}', a very small quantity of lymph will suffice to 

 inoculate a few sheep, which must be immediately severed from 

 the rest, to prevent the disease being conveyed by contact, and 

 thus introducing a natural sheep-pox, which, like its congener in 

 the human subject, is always more virulent than the artificially 

 produced. From these first inoculated, a supply of good healthy 

 lymph will be obtained for inoculating the remainder of the flock. 

 The j)laces best suited for the operation are the inner side of the 

 flap of the ear, or the under part of the tail, close to the root. The 

 instrument employed is a kind of needle made for the purpose, 

 with a fine, somewhat flattened point, which, having been dipped 

 in the virus, is carefully inserted between the upper and second 

 skin, cautiously avoiding piercing so deeply as to draw blood, 

 which is found to render the success of inoculation less certain. 

 Of course, in the absence of such a needle, a lancet will answer 

 the purpose. 



Time for Inoculating. — The most favourable season for yearly 

 inoculation is late in the spring, or early in the autumn, say the 

 latter half of April; or from the beginning of September to the 

 middle of October. In cases of feared infection there is unhappily 

 no room for choice. 



Effects of Inoculation. — When the operation has proved ef- 

 fectual, symptoms of fever appear about the fourth or sixth day ; 

 the inoculated parts become red, and throw out pustules, which, 

 on the ninth or tenth day, will be found filled with a thin trans- 

 parent lymph, which is then fit to be used as inoculating virus. 

 As, however, even with the utmost care, many animals do not 



