What is the test for pleading guilty in a personal injury case?

In giving judgment against the defendant the court states: “It may be that the defendant intended to contract for some other corporation, although he denies this. That case was not pleaded. Since it was not pleaded the case fails to be decided on the basis that ‘a person is liable for his engagements (as for his torts) even though he acts for another, unless he can show that by the law of agency he is to be held to have expressly or impliedly negatived his personal liability’. Bowstead on Agency (15th Ed.), at 424, footnote 5, noting that he must name his principal as the person responsible. The defendant must plead facts that trigger that negation. It would not do for him to plead, for example, that he was agent for a company to be incorporated (which the evidence also suggests as a possibility) because that would not negate his liability under the rule in Kelner v. Baxter (1866), L.R. 2 C.P. 174. We need not address legal issues that would arise on different pleadings for a differently conducted case.”