With the use of his trusty microscope Hassall was able to identify foreign substances found in ordinary foods such as bread, bottled fruits, vegetables and meat. Hassall discovered that foods were being cut with all sorts of things such as chalk, sawdust, sand and gravel, and even poisons such as lead, copper and mercury.

Using poisonous additives in food was much the norm in those days, businesses frequently cut corners to save costs and no one policed them. It was thanks largely to the investigative work of Dr. Arthur Hill Hassall that various food acts were eventually passed and the regulatory bodies created that led up to the food quality controls that we now have in place today.

Hassall’s impact was revolutionary, but he did not limit his impact solely to food safety. As a sufferer of tuberculosis, Hassall moved to Ventnor on the Isle of Wight, favouring the location for its warmer microclimate. Not only did Dr. Hassall recuperate during his time here, but he also founded the Royal National Hospital for Diseases of the Chest, where tens of thousands of patients benefitted from improved health too.