ACT reading practice test 38

DIRECTIONS: Each passage is followed by several questions. After reading a passage, choose the best answer to each question and fill in the corresponding oval on your answer document. You may refer to the passages as often as necessary.


Natural Science

This passage is adapted from "Magnetic Attraction" by Robert L. Park, Prof. emeritus of Physics, U. of Maryland.

In the early 16th century, the power of lodestone
(magnetite) to attract iron filings without touching
them suggested great power. Paracelsus, the famous
Swiss alchemist and physician, began using powdered
05lodestone in salves to promote healing. William Gilbert,
however, physician to Queen Elizabeth I and father
of the scientific study of magnetism, pointed out that the
process of grinding the lodestone into powder destroyed
the magnetism. Nevertheless, a century later, magnetic
10cures were introduced into England by Robert Fludd as a
remedy for all disease. The patient was placed in the
boreal position with the head north and the feet south
during the treatment.
By far the most famous of the magnetizers was Franz
15Mesmer (1734-1815), who carried the technique from
Vienna to Paris in 1778 and soon became the rage of
Parisian society. Dressed in colorful robes, he would
seat patients in a circle around a vat of "magnetized
water." While Mesmer waved magnetic wands over them,
20the patients held iron rods protruding from the vat. He
would later discover that the cure was just as effective
if he left the magnets out and merely waved his hand.
He called this "animal magnetism."
Benjamin Franklin, in Paris on a diplomatic assignment,
25suspected that Mesmer's patients did indeed benefit from
the strange ritual because it kept them away from the
bloodletting and purges of other Paris physicians. Those
physicians bitterly resented Mesmer, an outsider who
was attracting their most affluent patients. At the
30urging of the medical establishment, King Louis XVI
appointed a royal commission to investigate his claims.
This remarkable group included Franklin, then the
world's greatest authority on electricity; Antoine
Lavoisier, the founder of modern chemistry; and Joseph
35Guillotine, the physician whose famous invention would
one day be used to sever the head of his friend Lavoisier.
The commissioners designed a series of ingenious
tests in which some subjects were deceived into thinking
they were receiving Mesmer's treatment when they were
40not, and others received the treatment but were led to
believe they had not. The results established beyond any
doubt that the effects were due solely to the power of
suggestion. Their report, never surpassed for clarity or
reason, destroyed Mesmer's reputation in France, and he
45returned to Vienna.
Nevertheless, magnetic therapy eventually crossed
the Atlantic. Its most famous practitioner in the United
States was Daniel Palmer, who in 1890 opened Palmer's
School of Magnetic Cure in Davenport, Iowa. Like Mesmer,
50 Palmer soon discovered that his patients recovered
just as quickly if he omitted the magnets and merely
laid on hands. Thus was founded "chiropractic therapy,"
and the school became Palmer's College of Chiropractic.
In recent years, an enormous amount of research has
55been done on the effect of magnetic fields on the human
body, driven not by magnetic therapy, but by safety
considerations associated with the phenomenal growth in
the use of magnetic resonance imaging (MRI) for medical
diagnoses and research. MRI subjects the whole body to
60a magnetic field about a hundred times stronger than the
localized field of even the most powerful therapy magnet.
Happily, no ill-effects have been found from exposure to
MRI fields. Indeed, there are almost no effects at all-
just a few reports of faint sensory responses, such as a
65slight metallic taste and visual sensations of flashing
lights if patients move their eyes too rapidly. The fact
is that the stuff we're made of just isn't very magnetic.
That's why scientists were surprised two years
ago when Dr. Carlos Vallbona at the Baylor College of
70Medicine in Houston reported results of a double-blind
trial of magnets in the treatment of 50 patients suffering
post-polio pain. Some of the patients were treated with
commercial therapy magnets; others were treated with
sham magnets. Seventy-six percent of those treated
75with real magnets reported a decrease in pain, while
only 19 percent receiving the placebo felt an improvement.
The most frequent claim, which Vallbona supports, is that
magnets promote the flow of blood to the treated area.
It's easy to check. An excess of blood shows up as a
80flushing or reddening of the skin. That's why the skin
turns red when you apply heat; blood is being diverted
to the heated area to serve as a coolant. But you will
discover that placing a magnet of any strength against your
skin produces no reddening at all. There is no indication
85that Vallbona tried this.
The argument is that blood, because it contains
iron, should be attracted by the magnets. The iron in
hemoglobin, however, is not ferromagnetic. The hemoglobin
molecule itself is very weakly paramagnetic, but the fluid
90that carries the red cells, consisting mostly of water,
is diamagnetic-it is weakly repelled. Indeed, small
animals have even been levitated in powerful magnetic
fields.
As medical scams go, magnet therapy may not seem
95like a big deal. Magnets generally cost less than a visit
to the doctor and they certainly do no harm. But magnet
therapy can be dangerous if it leads people to forego
needed medical treatment. Worse, it tends to reinforce
a sort of upside-down view of how the world works,
100leaving people vulnerable to predatory quacks if they
become seriously ill. It's like trying to find your way
around San Francisco with a map of New York. That
could be dangerous for someone who is really sick-
or really lost.

1. One of the main ideas established by the passage is that:

A. Benjamin Franklin helped to start a feud between Franz Mesmer and other physicians.
B. English scientists did more than Swiss ones to develop the science of magnetic therapy.
C. if it hadn't been for Franz Mesmer, we wouldn't have MRI technology now.
D. the alleged benefits of magnetic therapy are dubious at best.

2. Which of the following did the most to turn public opinion against Mesmer's theories?

F. The execution of Lavoisier
G. Benjamin Franklin's writings on electricity
H. The findings of the royal commission
J. The urging of King Louis XVI

3. The main purpose of the fifth paragraph (lines 46-53) is to establish that:

A. poorly supported medical theories became popular in the United States despite the lack of evidence.
B. Mesmer's theories were in fact not sufficiently disproved after all.
C. The bodies of some people are more magnetic than those of others.
D. Daniel Palmer ended up being a more important scientist than Franz Mesmer.

4. The passage states that, on the whole, human blood is actually:

F. ferromagnetic.
G. repelled by magnetic fields.
H. predominantly composed of iron.
J. capable of levitating small animals.

5. The passage notes that the MRI:

A. was invented in 1890.
B. is used primarily to treat post-polio pain.
C. promotes the flow of blood.
D. is about 100 times stronger than a therapy magnet.

6. As it is used in line 76, the word placebo most nearly means:

F. phony treatment.
G. powerful magnet.
H. traditional cure.
J. psychological boost.

7. As it is used in line 100, the word quacks most nearly means:

A. theories.
B. treatments.
C. dishonest therapists.
D. animal-borne diseases.

8. The passage indicates that skin turns red when exposed to heat because:

F. heat is absorbed and stored in the skin.
G. one function of blood is cooling hot skin.
H. hemoglobin is very weakly magnetic.
J. humans are not very magnetic.

9. The passage most strongly emphasizes that the process of bloodletting was:

A. an important step in the development of magnet therapy.
B. still popular in France long after it had ceased to be popular in America.
C. harmful enough to make magnet therapy appear beneficial.
D. indirectly involved with the discovery of hemoglobin.

10. According to the passage, the only legitimate experiment that could be interpreted as supporting magnet therapy was conducted by:

F. Benjamin Franklin.
G. Daniel Palmer.
H. William Gilbert.
J. Carlos Vallbona.