Penicillin nontoxic in humans by first performing toxicity tests in animals and then on humans. His subsequent experiments on penicillin's response to heat and pH allowed Fleming to increase the stability of the compound. The one test that modern scientists would find missing from his work was the test of penicillin on an infected animal, the results of which would likely have sparked great interest in penicillin and sped its development by almost a decade. The importance of his work has been recognized by the placement of an International Historic Chemical Landmark at the Alexander Fleming Laboratory Museum in London on
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