Your doll is called a boudoir doll or bed doll. These dolls were not made for children to play with, but to sit on the bed and look pretty - although of course many were played with. Your doll's head is not porcelain, but a material called composition, which is a mixture of sawdust and glue and other ingredients, poured into a mold and baked, then painted. (If it were porcelain, you wouldn't be able to nail a wig on without breaking it!) Composition was the most common material that dolls were made from in the first half of the 20th century.
Identifying the maker of a boudoir doll is tricky unless there are markings or unusual features - and impossible from such a tiny photo. But if you Google "boudoir doll" you can find out more about them.