Of all the household, he alone would be likely to recognize the symptoms of strychnine poisoning, and yet we find him the only member of the family to uphold strenuously the theory of death from natural causes. 
Along with strychnine poisoning, he would be able to deal with a snake bite.
mnli hypothesis: Along with strychnine poisoning, he would be able to deal with a snake bite. premise: Of all the household, he alone would be likely to recognize the symptoms of strychnine poisoning, and yet we find him the only member of the family to uphold strenuously the theory of death from natural causes. 