The reason Pulque appears here is because it has been told that authentic Pulque is fermented from the spit of people who chew the maguey plant.
Pulque, a fermented beverage derived from juice of the maguey (agave) was the historical predecessor of mescal and tequila which wielded a heavy sociological influence during both Pre-Hispanic and Colonial periods of Mexican history. Maguey was one of the most sacred and important plants in ancient Mexico and had a privileged place in mythology, religious rituals and the meso-american economy. Pulque first appeared in Indian stone carvings about 200-200 AD.
Pulque is another traditional beverage (3-4 % alcohol) made from the juice of the maguey or agave plant. Is this beverage the same as tequila? No, tequila is fermented and destilled to make a strong alcohol, while pulque is a milky , slightly foamy and somewhat viscous beverage made by fermeting (not destilling) the fresh sap of certain types of maguey.