Canton, now Guangzhou, was the center of foreign and international trade in China during the period of the late Qing dynasty.

Canton was the only city in China where foreigners were allowed to set foot, thereby making it the only place where European and Chinese merchants could trade.

Overall, because Canton was the only city in China that was open to foreign trade, medical mission work was made possible here and spread more easily.

However, his main goal in travelling to China was not to practice medicine; instead, it was to save the Chinese from idol-worshipping and introduce them to Protestantism and Christianity.

He first began work in the hospital by treating diseases in the eye because he was told it would be the fastest way to gain the trust of the Chinese.

In the later years of his life, he became a fervent promoter of medical missions and played an instrumental role in increasing their importance and popularity.

Colledge strongly believed that Christians were required to help the sick in China, and as a result, pushed Parker, his mentee, to open a hospital in Canton.

As a result, Parker soon found it impractical for the hospital to only treat eye illnesses, and it then opened up to all different types of diseases.

In 1842, Parker returned to Canton with his wife, Harriet Webster (who was the first Western woman to be granted residence in China), and reopened the hospital.

As a result, it was also involved in areas outside of the treatment of diseases, including medical education, research, social service work, and promoting public health to the surrounding community.

Not only was it the first hospital that brought the concept of public health to the city of Canton, but it is also sustainable, as it still exists today as one of the most prestigious ophthalmic institutes in the world.