For nearly two centuries, scholars have debated whether some 325 lines in the 1602 quarto edition of Thomas Kyd’s play “The Spanish Tragedy” were, in fact, written by Shakespeare.

Last year, the British scholar Brian Vickers used computer analysis to argue that the so-called Additional Passages were by Shakespeare, a claim hailed by some as the latest triumph of high-tech Elizabethan text mining.

But now, a professor at the University of Texas says he has found something closer to definitive proof using a more old-fashioned method: analyzing Shakespeare’s messy handwriting.

In a terse four-page paper, to be published in the September issue of the journal Notes and Queries, Douglas Bruster argues that various idiosyncratic features of the Additional Passages — including some awkward lines that have struck some doubters as distinctly sub-Shakespearean — may be explained as print shop misreadings of Shakespeare’s penmanship.