Note 173 — Chapter I

Dr. Bretschneider, after having read the above, wrote to me from Pekin that the cultivated sweet potato is of origin foreign to China, according to Chinese authors. The handbook of agriculture of Nung-chang-tsuan-shu, whose author died in 1633, asserts this fact. He speaks of a sweet potato wild in China, called chu, the cultivated species being kan-chu. The Min-shu, published in the sixteenth century, says that the introduction took place between 1573 and 1620. The American origin thus receives a further proof.