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.
As with arches, the springing of a dome is the level from which the dome rises. The top of a dome is the crown. The inner side of a dome is called the intrados and the outer side is called the extrados. The haunch is the part of an arch that lies roughly halfway between the base and the top.