healthy and aseptic, skin-grafts may safely be placed on them directly.
If, however, their asepticity cannot be relied upon, it is necessary to
scrape away the superficial layer of the granulations, the young fibrous
tissue underneath being conserved, as it is sufficiently vascular to
nourish the grafts placed on it.

#Treatment of Special Varieties of Ulcers.#--Before beginning to treat a
given ulcer, two questions have to be answered--first, What are the
causative conditions present? and second, In what condition do I find
the ulcer?--in other words, In what particulars does it differ from a
healthy healing sore?

If the cause is a local one, it must be removed; if a constitutional
one, means must be taken to counteract it. This done, the condition of
the ulcer must be so modified as to bring it into the state of a healing
sore, after which it will be managed on the lines already laid down.

#Treatment in relation to the Cause of the Ulcer.#--_Traumatic
Group._--The _prophylaxis_ of these ulcers consists in excluding
bacteria, by cleansing crushed or bruised parts, and applying sterilised
dressings and properly adjusted splints. If there is reason to fear that
the disinfection has not been complete, a Bier's constricting bandage
should be applied for some hours each day. These measures will often
prevent a grossly injured portion of skin dying, and will ensure
asepticity should it do so. In the event of the skin giving way, the
same form of dressing should be continued till the slough has separated
and a healthy granulating surface is formed. The protective dressing
appropriate to a healing sore is then substituted. _Pressure sores_ are
treated on the same lines.