Last year, when singer Lila Downs was feeling desperately sad, she did what so many Mexican women would have done. She went into the countryside and met a curandera, a woman trained in traditional healing arts.

"The main reason for my sadness was not being able to have a child," recalled Downs. "You become emotionally affected and start to damage your insides. La curandera told me 'you're going to go inside your body and you're going to ask your stomach to forgive you for not feeding it sometimes."

Downs, 40, whose mother is from Oaxaca, Mexico and whose father is from Minnesota, has made seven studio albums that have reflected her twin ancestries, but "Shake Away" (Manhattan Records) is perhaps the most deeply heartfelt. On several of its songs, her voice bursts out with howls that seem otherworldly. When she performed the title track at Brooklyn's Prospect Park last month, she literally squirmed on the floor of the stage as if she had become a rattlesnake, shaking away its old, dead skin.

"The indigenous tradition of self-transformation is very sacred to me," said Downs, who performs Monday at Town Hall in New York. "Some songs on the album reflect a Mexican legend when people can transfigure either into a jaguar, a black dog, or a serpent.

"The process for this album began with the song 'Skeletons,' which is about the mysticism of the relationship between man and woman, and a ghost called 'Skeleton Woman,'" said Downs. "I thought, how can we translate that musically? It seemed to me that most mysterious place musically in the U.S. is New Orleans."

The subtle presence of zydeco rhythms propel tracks like "Skeleton," "Little Man," and "Silent Thunder," while the mournful ballad "Yo Envidio El Viento (I Envy the Wind)" is a bit like a New Orleans funeral dirge. The strong jazz element felt throughout the album is anchored by her co-producer, jazz trumpeter Brian Lynch. Her husband, Paul Cohen, who grew up in Vineland, leads the band, playing the clarinet and saxophone

But the album also has a strong Mexican feel, both in its musical styles (norteno, cumbia, bolero) and its politics. Downs has been affected by the difficult times her people have faced of late. "I really needed to get those emotions out and that's why I wrote 'Perro Negro (Black Dog),' 'Justicia, (Justice)' and "Ojo de Culebra (Eye of the Snake).'"

For that trio of songs, Downs got some help from some impressive guest vocalists. Cafe Tacuba lead singer Ruben Albarran added his punk-influenced edge to "Perro Negro." La Mari, from the Spanish pop-flamenco group Chambao, harmonized on "Ojo de Culebra" and Spanish rocker Enrique Bunbury lent his brooding emotional style to "Justicia."

The blues rocker "Minimum Wage," tells of the plight of immigrant workers in the U.S.

"I want to make people confront the hate and fear of the past six years in this country," she said. "Since when do we look down on people who work hard? Isn't that a basic value of this country?"

Perhaps the most intriguing song on "Shake Away" is her radical re-make of the classic Santana hit "Black Magic Woman." Using Spanish lyrics to respond to the lead vocals of guest guitarist Raúl Midon, Downs explains the woman's side of the story.

"The lyrics in Spanish are about the way that we assume that because if a woman is powerful she automatically has some resource that is supernatural," said Downs. "They're about the mysterious powers that women have -- but that at the same time we can be just like any other person."

By Ed Morales