CLARA BARTON, PROFESSIONAL ANGEL By Elizabeth Brown Pryor University of Pennsylvania Press 444 pp. $19.95

BIOGRAPHY is a difficult genre and has its fashions. In the chronicles of pre-World War I, American women of achievement -- the tomboys who preferred boys' sports to girls', who could run, ride and throw a ball as well as their brothers, who excelled in studies, who grew up to be generous-hearted crusaders for humanitarian causes -- were familiar and popular figures.

They were epitomized in fiction by Louisa May Alcott's lovable and irrepressible character, Jo, beloved by generations of readers of Little Men, Little Women and Jo's Boys. Current biographers, however, do not find them quite so wholly admirable.

Elizabeth Brown Pryor's subject, Clara Barton, fits the pattern. Long acclaimed as a heroine here and abroad, she is the best-known of that cluster of 19th-century American women who found their horizons broadened and their limited opportunities extended by the Civil War. Her bravery and resourcefulness in supplying food and necessities to foot soldiers, and in nursing the wounded, brought her the status and attention she needed to continue a career of philanthrophy -- as "professional angel" -- which culminated in the foundation and direction of the American Red Cross. Her place in history was assured well before the women's movement stirred interest in women in history.

Now Pryor's biography raises questions familiar in our age of expose'. Can flaws in character -- in Barton's case, petty deceit, jealousy, the inability to share work or glory, etc. -- beget accomplishment? Can motivations other than altruism -- the thirst for notice, for instance -- nullify the good done? Pryor herself seems ambivalent, although she insists that Barton's lifework must not be "treated cynically." AS CURATOR of the Clara Barton House (once headquarters of the Red Cross) in Glen Echo, Md., Pryor had access to Barton's recently discovered secret diaries and a mass of personal correspondence, "some hundred thousand pieces," that had been bricked up in a closet. To some extent Clara Barton was a creation of her own myth. She felt the need to create a public image consonant with her public activities in wartime and wrote a series of statements and letters, "cleverly crafted for publication," in which her personality and achievements were idealized. At the same time -- perhaps because she lacked the confidante she perennially longed for -- she kept diaries in which she frankly detailed her fears, her insecurities, her schemes, "the small triumphs and ugly thoughts, the petty details which make up every life," as well as her recurrent bouts with crippling and incapacitating depression -- all aspects at odds with the balanced and serene face she wished presented to the world.

The diaries also record a hitherto unknown personal life. They tell of Clara's sense of herself as an unloved child, excluded from the family circle. "In reality her whole life had been spent in a search for that public acclaim that served as a salve for the indifference of her family." One of the most interesting revelations is of a battlefield romance during the siege of Charleston. It was an almost open love affair with a married officer and, as example, bears out Pryor's opinion that the lack of an established niche in scoiety made Barton vacillate between conformity and rebellion.

Connoisseurs of women's history will find the glimpses of 19th-century woman's life gleaned from these diaries instructive. Clara Barton spent 18 years as a teacher, first in her native Massachusetts, then in New Jersey. These years are exhaustively and somewhat repetitiously described by Pryor. Again and again Barton improved the schools she took over only to leave when she found herself underpaid and unappreciated (although always leaving behind devoted pupils, many of whom she was to meet again on the battlefield.) Her teaching career ended when, after she had established the first public school in New Jersey, it became so large and successful that the townspeople would no longer allow a woman to run it. Rather than become subordinate to a male principal, she resigned.

The account of her subsequent employment as clerk in the U.S. Patent Office -- a result of political patronage -- is documentation of the daunting difficulties women experienced in a government service newly open to them. They were paid much less than men. The conditions of work varied according to the prejudices of department heads. Some allowed women to work in the office; others required them to take copy home on a piecework basis. The few women so employed were open to slander and were often harassed. At one period Barton had to make her way to the office past rows of jeering, spitting men.

Hitherto Barton had preferred the company of men and depended on them as friends and patrons. Like many other women leaders, she began to see that her experience was general to her own sex and to understand the thrust of feminism and the suffrage movement. When she herself became a public figure, she became friends with women like Susan B. Anthony and Elizabeth Cady Stanton, but she was always chary of becoming fully identified with their movement and projects. She once paid to have an announcement reprinted rather than have her name on it.

As absorbing as this biography is, it is marred by an uneven style and awkward sentence structure. Chronology is allowed to bog down in detail. Dangling modifiers abound -- "while still at Andersonville, her name had finally been struck from the registers of the Patent Office." Slangy diction is often at odds with an otherwise scholarly approach: Clara "peddled to the press," took a "snort" of blackberry brandy, and found the town of Danville "a pleasant burg." One expects more vigilant editing from a university press, especially of a volume destined to be an important reference work for years to come. ::

Abigail McCarthy is a columnist for Commonweal and biographer of Jane Grey Swisshelm, a contemporary of Clara Barton.