One of the most infamous examples of unethical testing of humans by the government was the Tuskeegee Experiment where African American men were allowed to suffer from syphilis (when a cure was available) to further the study of the disease. This was without their knowledge or consent. Here is an article about the Tuskeegee Experiment.
http://www.npr.org/programs/morning/features/2002/jul/tuskegee/
After you have carefully read Chapter 14 in your textbook, please discuss the ethical issues surrounding research with human subjects.