Contagious Pleuro-Pneumonia of the Ox. 



465 



the wound will have become contracted to about half the extent 

 of that shown in the plate, and instead of a level surface there 

 will be a dry hard scab somewhat elevated above the skin. 

 Sometimes at this period the scab is accidentally rubbed oif, 

 leaving an imperfectly healed wound. The surface, however, 

 is very soon incrusted again from the drying of the exudation 

 which takes place. 



After the lapse of ten days to a fortnight from the time of 

 inoculation, the part will indicate what may be called the cha- 

 racteristic signs of a successful inoculation. There will be con- 

 siderable swelling from the top of the tail to three or four inches 

 above the point of inoculation ; but the chief peculiarity is the 

 " spreading " of the incision — a condition which is represented in 

 Plate II. Very often at this period a small quantity of matter 

 exudes from beneath the scab, as shown in illustration on the left 

 side. Under the microscope this is seen to consist of ordinary 

 pus corpuscles, with numerous blood discs, as depicted in the 

 subjoined drawing. 



Fig. 3. — Fluid exuded from beneath the scab covering the inoculated 

 part, magnified 500 diameters. 



Sometimes the spreading of the scab is followed imme- 

 diately by excessive swelling of the part ; the scab is thrown 

 off, and an unhealthy and irritable sore is presented, as shown 

 in Plate III. A portion of the tail is commonly cut off at this 

 stage of the local disease, with the view of arresting the further 

 progress of the exudation. This operation was performed in 

 the case from which the drawing in Plate III. was taken. A 



VOL. X. — S. S. 2 H 



