IXOCULATIOX AS A PREYEXTIOX OF PLEURO-PNEUMONIA. 27 



spoonful to each animal daily is enough^ continued till the 

 declioe of the inoculation. 



Favourable and UnfavouraUe Results, 



After the operation the animals are generally a little restless, 

 and to a close observer, some in a few days are evidently out of 

 sorts. They do not, however, go off their food, not in the 

 slightest degree, and in the case of milkers, there is no falling 

 off in the milk given. About the third or fourth day and from 

 that on to the sixth or seventh day, the tail, at the seat of 

 operation, begins to swell, the hair stumps stand straight out, it 

 is hot, painful on pressure, and of a reddish glazed appearance. 

 There is, however, no discharge from the incision. Following 

 close upon the above, the skin assumes a yellowish tint, and is 

 covered with bran-like scales of desquamating cuticle. About 

 the ninth day, occasionally earlier, but more often later, the 

 animal loses the power of raising the tail, and examination will 

 show that beads of amber-coloured lymph are exuding from the 

 skin around the seat of operation. This lympth is identical in 

 character and properties with that obtained from the lung, good 

 and successful inoculation being obtained from its use. The 

 appearance of this exudate is the most satisfactory evidence we 

 can get that inoculation has taken place, and there can be no 

 doubt, that when an animal exhibits it, such a one becomes 

 exempt from pleuro. If an animal fails in exhibiting any of 

 the foregoing signs of inoculation it is generally owing to one of 

 the following causes: — Having had the disease before operation; 

 having it at the time of operation, or from non-susceptibility, 

 instances of which I have frequently come across. Succeeding 

 the appearance of the eruption of lymph, the most favourable 

 course which the inoculation can now take is the occurrence of 

 a mild degree of fever, followed by gradual diminution of the 

 local action, drying of the eruption, and scabbing over of the 

 incision. The animal gradually recovers the use of the tail, and 

 the whole process is practically over in from three to four weeks. 

 A good many cases terminate in this the very mildest way, 

 compatible with protection, especially in the case of bullocks, 

 young stock, and calves. 



The majority, however, especially in the case of milk cows, 

 do not end so mildly. In those, following the appearance of the 

 eruption, we get changes of the following description : — The end 

 of the tail swells more, it becomes quite moist from coalescence 

 of the vesicles from which the lymph escapes. There is a 

 tendency for it to become dark hued and low in temperature 

 towards the tip. Nature terminates such cases when able to do 

 so, in one of two ways, either by the formation of an olfensive 

 sloughing sore, which after a time dries u]), leaving the tip of 



