What is the reason why Dezhen published Wonders Outside the Painting?

1873, China published the first photography monograph "Wonders Outside the Painting". The author of this book, De Zhen (1837 ~ 190 1), is a British doctor who loves photography and is familiar with Chinese and western arts.

Dezhen came to China in 1860 and worked as a physician in the British Embassy in China. She was employed by Wentong Museum, a school run by the Qing government to train translators, to teach physiology and medicine. Later, he served as the dean of Kyoto Stone Hospital. During this period, he constantly published some translations of photography knowledge in a chinese magazine Chinese and Western News. People know that he is proficient in photography, so they ask him to take pictures or ask how to take pictures. Therefore, Dezhen decided to write a book by photography after practicing medicine.