Pus is an exudate, typically white-yellow, yellow, or yellow-brown, formed at the site of inflammation during infection. An accumulation of pus in an enclosed tissue space is known as an abscess, whereas a visible collection of pus within or beneath the epidermis is known as a pustule or pimple.

Pus consists of a thin, protein-rich fluid, known as liquor puris, and dead leukocytes from the body's immune response (mostly neutrophils). During infection, macrophages release cytokines which trigger neutrophils to seek the site of infection by chemotaxis. There, the neutrophils engulf and destroy the bacteria and the bacteria resist the immune response by releasing toxins called leukocidins. As the neutrophils die off from toxins and old age, they are destroyed by macrophages, forming the viscous pus.

Bacteria that cause pus are called suppurative, pyogenic, or purulent. If the agent also creates mucus, it is called mucopurulent. Purulent infections can be treated with an antiseptic.

Despite normally being of a whitish-yellow hue, changes in the color of pus can be observed under certain circumstances. Pus is sometimes green because of the presence of myeloperoxidase, an intensely green antibacterial protein produced by some types of white blood cells. Green, foul-smelling pus is found in certain infections of Pseudomonas aeruginosa. The greenish color is a result of the pyocyanin bacterial pigment it produces. Amoebic abscesses of the liver produce brownish pus, which is described as looking like "anchovy paste". Pus can also have a foul odor.

James Daniel May (born 16 January 1963) is an English television presenter, journalist and writer. He is best known for his role as co-presenter of the award-winning motoring program Top Gear alongside Jeremy Clarkson , and Richard Hammond.

On Top Gear, May has the nickname "Captain Slow" for his careful driving style, a love of small underpowered cars and habit of getting lost and distracted while driving. However, in a July 2010 episode of Top Gear he drove a Bugatti Veyron Super Sport, reaching a speed of 417.6 kilometres per hour (259.5 mph). After his attempt the Bugatti test driver Pierre-Henri Raphanel took the car to 430 kilometers per hour (267.5 mph).

May has presented a variety of other programs on themes including science and technology, toys, cars, wine culture, and the plight of manliness in modern times. In addition he has released a variety of DVDs and books with similar themes, and wrote a weekly column for The Daily Telegraph's motoring section.

James May was born in Bristol, one of four children; he has two sisters and a brother. May attended Caerleon Endowed Junior School in Newport, then in Monmouthshire. He spent his teenage years in South Yorkshire where he attended Oakwood Comprehensive School in Rotherham and was a choirboy at Whiston Parish Church. He was also at school with Life On Mars and Ashes to Ashes star Dean Andrews. A keen flautist and pianist, he later studied music at Pendle College, Lancaster University. After graduating, May briefly worked at a hospital in Chelsea as a records officer, and had a short stint in Her Majesty's Civil Service.