Finlay was the man who first propounded the theory that yellow fever was spread by mosquitoes.
The scientist was of Of French and Scottish descent and was born in 1833 in Puerto Príncipe, which is now the Cuban city of Camagüey. He studied at Jefferson medical college in Philadelphia, Pennsylvania.
After he finished his studies in Havana and Paris Finlay settled in Cuba and opened a medical practice.
Appointed by the Cuban government in 1879 to work with a North American commission studying the causes of yellow fever, after two years Carlos Juan Finlay was sent as the Cuban delegate to the fifth International Sanitary Conference in Washington DC.
At the conference, th physician and scientist urged those present to study yellow fever vectors. Finlay would later theorise that the carrier of yellow fever was the mosquito Culex fasciatus, now known as Aedes aegypti.
When a US Army's Yellow Fever Board arrived in Cuba in 1900 the Cuban scientist Finlay sought to persuade it of his mosquito-vector theory.
Finlay's hypothesis were confirmed by the board's head, Dr Walter Reed of the US Army. This helped in starting the process to help the cause of eradication of yellow fever and saving many people especially those in South America, the Caribbean, Africa and the southern US who fell prey to the disease almost constantly.
In August 1915, Finlay passed away at the age of 81 at his home in Havana, Cuba from a seizure induced stroke.
Today's Google doodle has Carlos Juan Finlay's face amidst stagnant water, leaves in the water and mosquitoes breeding on them. The doodle credits the man and his hypothesis in via the art work on their home page as they salute the life saver - Carlos Juan Finlay whose theory and study continues to save many lives today almost 100 years after his death.