1. A preparation containing 0·7% scilliroside (the glucoside of red squill) had been tested as a poison for Rattus norvegicus and R. rattus.
2. The preparation has been found to be effective in the field against norvegicus but not against rattus.
3. Assayed against a strain of white rats, the preparation had an LD 50 for males of about 25mg./kg., and for feamales of about 5 mg./kg.
4. The LD 50 for adult Rhode Island Red fowls was greater than 400 mg. /kg. Pigs, dogs and cats were treated with doses up to 16mg./kg. without fatal results.
5. Silmurine was unpalatable to pigs, dose and cates, but fowls readily consumed a mash containing 1% Slimurine.