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.
Flat feet/fallen arches. Having flat feet is also known as having fallen arches, and means the arches of the feet are low or there are no arches. Flat feet may not cause any pain or problems, but strain can be caused to muscles and ligaments making it painful when walking.