The Dangerous Druggist

Action against D, a druggist, for the alleged negligent filling of a prescription. At trial, P's first witness is W, her family physician. W testifies that on January 1, in response to a call from P, she phoned D and prescribed for P a solution of paraldehyde, C₆H₆O₃, as a sedative and hangover relief. Unfortunately, D delivered a solution of formaldehyde, HCHO, a colorless compound used to manufacture fertilizers, dyes, embalming fluids, preservatives, and disinfectants. Formaldehyde is highly toxic to humans, and P was badly hurt when she gulped down half the bottle delivered by D.

In defense, D claims that W ordered formaldehyde. On cross-examination, D is asked whether he made a written record of the order. D replies that he did but that he threw it away. P's counsel moves to strike D's direct testimony.

What ruling and why?