Final answer:
Arsenic and mercury, while poisonous to bacteria, are also highly toxic to humans and have caused considerable health issues when found in the environment. The information illustrates the serious effects of these chemical agents through historical and modern examples, including the mass poisoning in Bangladesh and the Minamata disease in Japan.
Step-by-step explanation:
The process being referred to in the question is likely the use of a substance toxic to bacteria as a means to combat bacterial infection. In this context, antibiotics or antiseptic agents could fill the blank. However, based on the reference information provided, it seems that the topic is related to the harmful effects of chemical agents, such as arsenic and mercury, on human health. These agents, while poisonous to bacteria, have also had a severe impact on human populations when present in the environment at toxic levels. Arsenic has caused numerous health problems and even deaths due to its presence in drinking water, as seen in Bangladesh. Similarly, mercury poisoning affects the central nervous system, leading to severe health issues as was the case in Minamata, Japan.
It's also worth noting the historical context of intentional poisoning and the modern concerns of accidental poisoning from everyday products. Furthermore, the potential for bacteria like Bacillus anthracis to be used as biological weapons is mentioned, indicating the dual nature of substances in terms of toxicity and utility against pathogens.