Read this excerpt from Immigrant Kids.

The second doctor watched for contagious and infectious diseases. He looked especially for infections of the scalp and at the eyelids for symptoms of trachoma, a blinding disease. Since trachoma caused more than half of all medical detentions, this doctor was greatly feared. He stood directly in the immigrant's path. With a swift movement, he would grab the immigrant's eyelid, pull it up, and peer beneath it. If all was well, the immigrant was passed on.

The purpose of this excerpt is

to provide information about eye doctors and to explain how they traveled the immigrant’s path.
to provide information about eye disease and to explain its medical treatment.
to provide information about scalp infections and to explain how they can be prevented.
to provide information about trachoma and to explain how it was diagnosed among immigrants.