Benzylpenicillin of penicillin allergy. Use during pregnancy is generally safe. It is in the penicillin and β-lactam class of medications. Benzylpenicillin was discovered in 1929 by Alexander Fleming and came into commercial use in 1942. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. The wholesale cost in the developing world is about US$0.24–2.72 per day. In the United States a course of treatment costs $100–200. As an antibiotic, benzylpenicillin is noted to possess effectiveness mainly against Gram-positive organisms. Some Gram-negative organisms such as "Neisseria gonorrhoeae" and "Leptospira
Valentine tank According to the most popular one, the design was presented to the War Office on St. Valentine's Day, 14 February 1940, although some sources say that the design was submitted on Valentine's Day 1938 or 10 February 1938. White notes that "incidentally" Valentine was the middle name of Sir John V. Carden, the man who was responsible for many tank designs including that of the Valentine's predecessors, the A10 and A11. Another version says that Valentine is an acronym for Vickers-Armstrong Ltd Elswick & (Newcastle-upon) Tyne. The "most prosaic" explanation according to David Fletcher is that it was just an