320 THE DISEASES AND DISORDERS OF THE OX. 



with many of his tenants. In another village on the same estate 

 where no preventive measures were taken, not a single sheep was 

 left. This observer maintained that immediate inoculation 

 would not only generally save nine-tenths of sheep which were 

 unaffected, but that it would also lighten the disorder in the case 

 of those individuals of the flock which already showed signs of 

 disease. The great objection to inoculation is that inoculated 

 ovine-pox is quite as contagious as the natural disease itself; 

 and, moreover, the deaths may be at the rate of 20 per cent. 



Hence there is a great deal of danger in this operation, and it 

 is obvious that the care taken in regard to the selection of the 

 fluid and in the method of procedure cannot be too minute. 

 Especially is it necessary that pure lymph should be selected, 

 and deep punctures should on no account be made. Moreover, 

 the operation ought not to be performed on lambs that are less 

 than four and a half months old. The lymph should be taken 

 from those sheep which have had the disease in its mildest form, 

 and the operation should be performed at a time when the 

 weather is genial and temperate, as may be the case late in spring 

 or early in autumn. 



The places usually selected are the under side of the flap of 

 the ear, or the under surface of the tail, close to the root. A 

 needle with a fine flat point, or a lancet dipped in the virus, 

 should be carefully inserted between the upper and the second 

 ■skin. Great care should be taken to avoid piercing so deeply as 

 to draw blood, since large punctures are sure to be followed by 

 extensive or deep and dangerous sloughing. In fact, the 

 scratches cannot be too superficial. There should not be more 

 than three punctures, and they should be about two inches apart, 

 so as to prevent the probability of an extension of the inflam- 

 mation from one to another. It is well to have one on either 

 side of the abdomen and a third on the inner surface of the thigh. 

 The virus, after being introduced, remains dormant for a few 

 days. If the inoculation takes, a red speck appears around 

 the incision, and increases until it is as large as half-a-crown, 

 then depression of its centre occurs, together with constitutional 

 disturbance of the animal, and perhaps an eruption. If no signs 

 appear by the eighth day, the inoculation may be supposed to have 

 failed. The vesicles produced by ovination will yield lymph 

 about the eighteenth day. Some say that after the lymph has 



