12      BULLETIN 793, U. S. DEPARTMENT OF AGRICULTURE. 
water. This was renewed daily. As inagnesic sulphate forms an in- 
soluble compound with lead, this solution tended to neutralize the 
lead particles as they were given off into the intestine. The color of 
the feces in birds treated changed at once from bright green to olive 
brown. This treatment was tried on a small number of ducks, and 
about 50 per cent recovered. The method is of interest as an experi- 
ment but has little or no practical value, as the time required for 
treatment was prolonged and the result was somewhat uncertain. 
Various suggestions have been made to combat this trouble but 
none is at all efficacious. Some persons, supposing that the birds 
swallowed the shot because of a lack of gravel on their feeding ground, 
have proposed supplying grit and sand in the marshes in the belief 
that the birds would use this and not eat the shot. As has been said 
before, ducks in feeding seem to swallow any small, hard objects that 
they encounter, so that such supplies of gravel would be of no aid in 
preventing lead poisoning. It has also been suggested that the mud 
flats be harrowed in some way to cause the shot to sink beyond reach. 
This, howvever, would be of no avail, as ducks in feeding often dig in 
soft mud to a depth of 12 to 16 inches. 
Statistics on the number and species of birds affected by lead 
poisoning from eating pellets of shot will be of interest, and it is 
hoped that sportsmen and others will report cases that come to their 
attention. There can be no doubt that the trouble is found in many 
extensive marsh areas throughout the United States in addition to 
those mentioned in this report. 
ADDITIONAL COPIES 
OF THIS PUBUCATION MAY BE PROCURED FROM 
THE SUPERINTENDENT OF DOCUMENTS 
GOVERNMENT PRINTING OFFICE 
WASHINGTON, D. C. 
AT 
5 CENTS PER COPY 
V