Robert Collins might not be around had it not been for a mysterious, kindhearted Latina who was at Goliad when Texans fought for independence in 1836. Now 72, Collins had never heard of the "Angel of Goliad" until he read about Francisca Alvarez in the newspaper a few years ago. His ancestor, John P. Collin, came to Texas from Louisiana to serve in the war. Collin was a young medic when he somehow eluded execution at Goliad. The mystery runs so deep that Collins can't say for certain that Alvarez saved his forebear. "Naturally, he survived, or I wouldn't be...