800 DISEASES OF DOMESTICATED BIRDS 
the patient because in birds dry gangrene occurs very quickly in parts 
from which the circulation is cut off. (Klee.) 
FROZEN COMB AND WATTLES 
When freezing of the appendages of the head occurs, thawing may 
be accomplished by smearing with vaseline, and manipulating with 
the fingers. In case of serious injury of the comb or wattles, they 
may be removed as described under dubbing. 
INCISION OF THE CROP 
This operation is frequently necessary in order to evacuate the 
contents of the organ when impaction is present, and is comparatively 
harmless in fowls. After removing the feathers from the operative 
area, an incision is made parallel to the axis of the neck, and as 
long as the circumstances require. The material is removed by 
kneading, and the use of forceps. Healing occurs in about a week 
after suturing. Feeding must be restricted for a few days to bread 
and milk but water may be given without limit after 36 hours. 
PREVENTION OF FLIGHT 
It is sometimes necessary to deprive birds of the power of flight 
either temporarily or permanently. To arrive at this result it may 
_ be necessary only to cut off the large feathers on one wing, or to pre- 
vent the extension of the member by some mechanical device. What- 
ever the method employed it should be applied to but one wing. The 
effect in preventing flight is accomplished more by destroying power 
of maintaining equilibrium than in reducing wing surface. 
Permanent elimination of the primary wing feathers may be ac- 
complished by severing the region of the wing corresponding to the 
hand. A cut is made with scissors on a line so as barely to leave 
intact the bone corresponding to the thumb. The proper location for 
the amputation may be determined by making the cut barely include 
the primary feathers. Hemorrhage may be arrested by cauterizing 
or by applying perchloride of iron. 
The operation is very simple and quite harmless. Very little 
trace is left, for the stump is covered by the feathers of the thumb. 
When the wing is folded, the absence of the primary feathers is not 
noticeable. 
