The Powder-Puff Killer

On June 1 at 6 p.m. Mrs. D, wife of Dr. D, awakens from her nap and begins to dress and apply cosmetics for the opera. She opens her compact and takes out her powder-puff. Suddenly a spider emerges, springs on Mrs. D, bites her, and absconds. That night Mrs. D is in bed in pain and is feverish. Dr. D gives her a hypodermic injection. The injection may be demerol or it may be air bubbles. Shortly after the injection Mrs. D dies. Dr. D is charged with premeditated murder by spider bite and air bubbles.

(1) At Dr. D's trial the prosecution calls Dr. T, a toxicologist, as its first witness. On direct examination Dr. T states that upon testing the cadaver of Mrs. D for venom, he found spider venom. On cross-examination the following occurs:

Q: How much venom did you find?

A: About one-half cc.

Q: What kind?

A: Black widow.

Q: You also found traces of demerol, didn't you?

By the D.A.: Objection.

What is the basis of the district attorney's objection? What ruling should the court make? Why?

(2) Suppose that after Dr. T is excused the prosecution calls M, Mrs. D's mother. M testifies that she saw D open his wife's compact and put a spider into it. On cross-examination M is asked if she has made a will that disinherits Dr. D. The D.A. objects.

What ruling and why? What general rules concerning the scope of cross-examination may be derived from this example?