4 BULLETIN 793, U. S. DEPARTMENT OF AGRICULTURE. 
breast, and in a very sliort time the birds are unable to fly. (PL I, 
figs. 1 and 2.) Following this the wings begin to droop from the 
sides. In many cases the extensor muscles supporting the wing tip, 
that portion of the fore limb homologous with the hand, are seriously 
affected, and the wing hangs from the carpal joint, a symptom 
strikingly like the " wrist drop " found in many cases of lead poison- 
ing in man. The wings float loosely on the surface when the affected 
birds are in the water, and in severe cases the tips of the primaries 
may drag as the bird walks about on the ground. Other muscles are 
affected as well. When the bird is standing, the breast is depressed 
and the tail droops. (PL II, fig. 2.) 
After a few days birds often experience difficulty in walking and 
may fall as they attempt to turn around. This paralysis of the legs 
grows until the body can no longer be supported, and in moving 
about the birds slide along on the breast. (PL I, figs. 1 and 2.) 
This loss of function in the muscles is not always symmetrical; in 
several cases muscles on the left side were more severely affected than 
on the right. This was especially noted in the leg muscles. In many 
of the living birds studied the poisoning due to ingested shot was 
acute, and death came in a few days. In others the condition be-* 
came chronic, and the birds, much emaciated, lived from two to five 
weeks. Often an adult mallard would waste away until the large 
muscle masses of the breast were reduced to slender fasciae that were 
barely sufficient to cover the sternum. 
The feces of affected birds are thin and watery and stained green. 
This color is a well-marked symptom. When fecal matter comes 
largely from the rectum the green is very dark, but when mixed with 
renal matter in the cloaca it becomes paler. In this case the green 
color, though lighter, is remarkable for its brightness. The body 
temperature of affected birds is normal, unless the individual is 
anaemic, when it is subnormal. 
In weak birds the eye was usually very bright and the muscle con- 
trolling the nictitating membrane not affected. During field work in 
Utah this point was used as a ready means of distinguishing these 
birds from individuals helpless from poisoning due to alkalies. 1 
The heart of a bird suffering from lead poisoning is affected, and 
the bird may die suddenly after fright or exertion. Captives under 
observation were liable to spasms after they had become much weak- 
ened, during which they fell on the breast with head and wings ex- 
tended, and were agitated by slight but rapid tremors. In some 
cases this caused the lower mandible to rattle against the upper. 
These spasms were followed by periods of weakness, when for a time 
the birds lay motionless, but later were able again to walk about. The 
1 Cf. Wotmore, Alexander. The Duck Sickness in Utah: Bull. 672, U. S. Dept. AgT., 
pp. 1-25. 191^. 
