Why did Louis Pasteur do what he did?

Pasteur lived in the time of the theory of spontaneous generation - the thought that life could simply emerge out of thin air. Pasteur disproved this assumption.

Pasteur founded the science of microbiology and proved that infectious diseases are caused by micro-organisms. This became known as the "germ theory" of disease. He was the inventor of the process of pasteurization and also developed vaccines for several diseases including rabies. The discovery of the vaccine for rabies led to the founding of the Pasteur Institute in Paris in 1888.
Louis Pasteur made major contributions to chemistry, medicine, and industry that have greatly benefited humanity.
The reason's he did the things he did was because:
1. He had a great love and devotion for science.
2. Louis Pasteur had a great respect for others, and it was his hope to help save humanity, rather than to see it destroyed.

Louis pasteur and his wife had 5 children together, but only 2 of them survived to adulthood, he lost 1 to a brain tumor and 2 to typhoid disease, this fuled his passion, for saving life as he didnt ever want anyone to have to suffer the tragedy of having to bury their own children.