Saliva is a watery substance formed in the mouths of animals, secreted by the salivary glands. Human saliva comprises 99.5% water, plus electrolytes, mucus, white blood cells, epithelial cells (which can be used to extract DNA), glycoproteins, enzymes (such as amylase and lipase), antimicrobial agents such as secretory IgA and lysozyme.
Take it on the arches does not mean simply Leave. It means Walk away. If Travis continues to break the chops of his dispatcher, he will not be driving a cab tonight. He will be walking home. I had no idea it was such an obscure term. It is dated, to be sure.
An arch is a curved structure that spans an elevated space and may or may not support the weight above it. Arches may be synonymous with vaults, but a vault may be distinguished as a continuous arch forming a roof. Arches appeared as early as the 2nd millennium BC in Mesopotamian brick architecture, and their systematic use started with the ancient Romans, who were the first to apply the technique to a wide range of structures.