So a 74xx244 works at a commercial operating temperature, while a 54xx244 which is the same logic device [maybe the same pinout, and package] will continue to operate to the military operating temperature range [which is wider].
A distemper vaccine is more than a preventive against canine distemper virus. This vaccine, considered a core vaccine for all dogs in the United States, also protects against a host of other diseases you may not know your dog is susceptible to. These can include adenovirus, parvovirus, and others.
distemper. n. 1. (Veterinary Science) any of various infectious diseases of animals, esp canine distemper, a highly contagious viral disease of dogs, characterized initially by high fever and a discharge from the nose and eyes. See also hard pad, strangles. 2. (Medicine).