I enjoy reading the questions at the end of chapters in old textbooks. They provide so much insight into what the book author considered important. These questions in a hundred-year-old home economics textbook at the end of a section about milk made me realize that the issues and concerns were somewhat different back then.
In case you are wondering, here is what it said earlier in the book about clean milk:
Clean milk is the only safe milk. Dirty milk may contain disease germs that cause typhoid fever, tuberculosis, or other diseases. Clean milk comes from clean cows kept in clean barns. The milk must be handled by persons with clean hands and clean clothes, and it must be placed in clean pails, bottles, or pans.
If milk is purchased from a store or dairy wagon it should be in bottles, tightly covered. The bottles must be kept in a cool place where there are no flies. If a bottle of milk is put in the refrigerator it must always be tightly covered.
Elementary Home Economics (1921) by Mary Lockwood Matthews