The masters think a slave who chooses to work during his time off doesn't deserve the time off, and a slave who doesn't work to save enough throughout the year to buy whiskey for the holidays is considered lazy.
An adjuvant is a substance added to some vaccines to enhance the immune response of vaccinated individuals. The aluminum salts in some U.S. licensed vaccines are aluminum hydroxide, aluminum phosphate, alum (potassium aluminum sulfate), or mixed aluminum salts.
The field of DNA vaccination is developing rapidly. Vaccines currently being developed use not only DNA, but also include adjuncts that assist DNA to enter cells, target it towards specific cells, or that may act as adjuvants in stimulating or directing the immune response.