Lymph is a fluid that circulates throughout the body in the lymphatic system. It forms when tissue fluids/blood plasma (mostly water, with proteins and other dissolved substances) drain into the lymphatic system. It contains a high number of lymphocytes (white cells that fight infection).
Puppies normally get their first shots around 8 weeks old, but they can be given earlier if needed (ie with stray, abandoned pups or those who were formula fed). Three sets of combination vaccinations (a shot that protects against more than one disease) given at 3 week intervals. 8 weeks - first round.
According to the American Animal Hospital Association (AAHA), puppies should be vaccinated every three to four weeks between the ages of 6 and 16 weeks (i.e. at 6, 10 and 14 weeks or at 8, 12 and 16 weeks), with the final dose given between 14 and 16 weeks of age.