Species that typically live in soil water, and (10)elsewhere rarely multiply on the skin. Un- damaged skin is also unfavorable to most human pathogens. The skin is too acid and too arid for some species. The constant shedding of the surface skin layers further hinders the establishment of invaders. The most interesting (15)defense mechanism, however, results from the metabolic activities of the resident flora. Unsaturated fatty acids, an important com- ponent of the lipids in sebum collected from the skin surface inhibit the growth of several bac- (20)terial and fungal cutaneous pathogens. These acids are a metabolic product of certain gram- positive members of the cutaneous community, which break down the more complex lipids in freshly secreted sebum.
17. The primary purpose of the passage is to
(A) offer an analysis of metabolic processes
(B) detail the ways in which bacteria and fungi can be inhibited
(C) describe mechanisms by which the skin protects itself against pathogens
(D) analyze the methods whereby biological systems maintain the status quo
(E) provide a specific example of the skin's basic defense against pathogens
18. The "resident flora" mentioned in line 16 refer to
(A) "Unsaturated fatty acids" (line 17)
(B) "sebum collected from the skin surface" (lines 18-19)
(C) "bacterial and fungal cutaneous pathogens" (lines 19-20)
(D) "certain gram-positive members of the cutaneous community" (lines 21-22)
(E) "more complex lipids" (line 23)
19. Among the natural defense of the skin against pathogenic organisms are all of the following EXCEPT the
(A) dryness of the skin
(B) acidity of the skin
(C) tendency of the pathogens toward homeostasis
(D) shedding of surface layers of the skin
(E) metabolic breakdown of lipids
20. The author presents her material in which of the following ways?
(A) Stating a problem and then supplying a solution
(B) Presenting a phenomenon and then analyzing reasons for it
(C) Providing information and then drawing a conclusion from it
(D) Making a general statement and then arguing by analogy
(E) Making an inference and then developing it by illustration
"Masterpieces are dumb." wrote Flaubert. They have a tranquil aspect like the very products of nature, like large animals and mountains. He might have been thinking of (5) War and Peace, that vast, silent work, un- fathomable and simple, provoking endless questions through the majesty of its being. Tolstoi's simplicity is "overpowering, says the critic Bayley. "disconcerting" because it comes (10)from "his casual assumption that the world is as he sees it" Like other nineteenth-century Russian writers he is "impressive" because he "means what he says." but he stands apart from all others and from most Western writers in his (15)identity with life, which is so complete as to make us forget he is an artist. He is the center of his work, but his egocentricity is of a special kind, Goethe, for example, says Bayley, "cared for nothing but himself. Tolstoi was nothing but (20) himself."
For all his varied modes of writing and the multiplicity of characters in his fiction, Tolstoi and his work are of a piece. The famous "conversion" of his middle years, movingly (25)recounted in his Confession, was a culmination of his early spiritual life, not a departure from it. The apparently fundamental changes that led from epic narrative to dogmatic parable, from a joyous, buoyant attitude toward life to pessi- (30)mism and cynicism, from War and Peace to The Kreuler Sonata, came from the same restless, impressionable depths of an independent spirit yearning to get at the truth of its experience. "Truth is my hero," wrote Tolstoi in his youth, (35)reporting the fighting in Sebastopol. Truth remained his hero-his own, not others' truth. Others were awed by Napoleon, believed that a single man could change the destinies of nations, adhered to meaningless rituals, formed their (40)tastes on established cannons of art. Tolstoi reversed all preconceptions; and in every rever- sal he overthrew the "system," the "machine," the externally ordained belief, the conventional behavior in favor of unsystematic, impulsive life, (45)of inward motivation and the solutions of independent thought.
In his work the artificial
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