1. What is the main reason for conducting the experiment in which the author participates?
(a) A need to understand the so-called "visionary" experiences associated with the drug.
(b) A need to catalogue the psychological effects of the drug on someone who already has a psychiatric illness.
(c) A need for more comprehensive information regarding the drug's long-term side effects.
(d) A need to understand why the drug has been used in religious and secular ceremonies.

2. According to Huxley, what causes negative visionary experiences?
(a) An allergy to mescalin.
(b) A negative outlook on life.
(c) The way that mescalin is broken down in the body.
(d) Mental illness.

3. What is the difference between the two techniques the author describes in Appendix 1?
(a) One is completely non-toxic, while the other has some lasting side effects.
(b) One involves chemicals, while the other makes use of physics.
(c) One is costly, while the other is inexpensive.
(d) One is well-researched, while the other is relatively unknown.

4. According to the author, what is the most important effect of the first technique mentioned in Appendix 1?
(a) Subjects perceiving that they are able to communicate with a higher power.
(b) The rarity of negative side effects in users.
(c) The cheapness and availability of the substance used.
(d) A marked increase in the subject's ability to see things with their eyes closed.

5. What is the biggest difference between dreams and visions, according to the author?
(a) Visions are often similar to religious experiences, but dreams usually aren't.
(b) Visions can be induced, while dreams only happen randomly.
(c) Color is rare in dreams, but is always present in visions.
(d) Dreams can be had while awake or asleep, while visions only occur when one is awake.