The milk is human milk, expressed by the wet nurse. An Jing's first birth of four sons greatly depleted her vitality, so she had no milk of her own and could only hire a wet nurse. However, Xiao Changyi did not like the idea of a wet nurse holding his children and nursing them, so the milk was first expressed by the wet nurse and then fed to the four children by Xiao Changyi.
An Yiyun, who had originally been held quietly in An Jing's arms without crying, began to wail loudly the moment she smelled the medicine. Even though she did not understand anything yet, every time she smelled the medicine it meant it was for her to drink, a practice that had continued for several days. Unable to speak or express herself properly, all she could do was cry.
But because of her poor health, even her intense crying could not last long, and she soon could only sob intermittently, gasping for breath in a weak and pitiable state.