310 SCOTTISH METROPOLITAN VETERINARY MEDICAL SOCIETY. 
withdraws it, leaving the saturated thread in the tail; and after 
cutting any too long ends of the worsted off, the operation of 
inoculation in its first stage is complete. 
Within two or three days after inoculating the part operated 
upon becomes slightly swollen, painful, and erythematous, but 
there is no discharge from the orifice, similar to what we get from 
the introduction of an ordinary seton; the swelling locally 
increases; and although the tail above may not be in the least 
degree swollen, the animal is not able to lift it. About the ninth 
day the skin is observed to take on a yellowish tinge, there is a 
rapid desquamation of the cuticle, followed by an exudation on 
its surface of beads and amber-coloured lymph, similar to that 
introduced, and possessing similar properties. It usually takes 
from nine to twelve or thirteen days for the exudate to make its 
appearance. Occasionally a longer time is required, but when it 
does appear, inoculation may be considered to have been success¬ 
ful, and the second stage is complete. 
There are two courses now open to the operator, and much of 
the success of the operation depends upon which he will adopt. 
He may elect not to interfere with the process, but allow it to 
run its course, which, under ordinary circumstances, will be death 
and wet gangrene of the end of the tail, followed by its being 
thrown off. This is usually done by nature establishing a line of 
demarcation above the gangrenous end, sufficiently powerful to 
resist the spread of the gangrene. It is, however, impossible to 
be certain of this line being drawn, or the position of it; and the 
risk is then materially increased of gangrene spreading upwards 
towards the root of the tail, where it becomes highly dangerous. 
Tor this reason, I advise the non-adoption of the plan of allowing 
the process to run its own course. I find the best plan is to 
remove the end of the tail, when once inoculation is fairly 
established. There are cases in which this must be done even 
earlier, and there are others in which it may have to be accom¬ 
plished more than once ; as, for instance, when the sudden setting 
in of coldness of the end of the tail indicates the death of the 
part. The best guide we have for knowing at what place to 
amputate is obtained by examining carefully the end of the tail. 
The part to come off may not necessarily be cold, but it will be 
wet with exudate, and probably somewhat discoloured for an inch 
or so above it. I find that where amputation is practised early— 
say on the twelfth to the fourteenth day—that it is not necessary 
to make the division more than a finger’s breadth or so above the 
upper incision made in inoculating. The amputation should be 
followed by profuse bleeding. If not, and if on examining the end 
of the stump w T e find clotting of blood in the vessels, amputate 
again higher up till bleeding follows. Neglect of this measure is 
apt to be followed by gangrene; in fact, the engorged vessels are 
an indication that it has already set in. 
Where a number of animals have been operated upon, you will 
find that several of the tails will, after amputation of the inocu- 
