Rinse spinach well and then remove stems. In a large saucepan, combine 1 C. stock, garlic and onion. Bring to a boil over high heat. Add spinach and cook, stirring, for 2 minutes. Then add the rest of the chicken stock and bring to a boil. In a small bowl, combine cornmeal and flour. In a slow stream, add stock, sitrring as you pour. Cover and simmer over low heat for 30 minutes. Puree soup, in batches if necessary, in a food processor or blender. Season with salt, pepper and nutmeg.