Note 169 — Chapter XIX
Reading edition
The Portuguese and Brazilians call it seringa, or syringe, in which form it is still used extensively, injections forming a great feature in the popular system of cures. The tree mentioned above yields most of the rubber of commerce, and is considered distinct from the species in Guiana, S. elastica; while the rubber from the Upper Amazon and Rio Negro comes from the S. lutea and S. brevifolia. Agassiz puts milk-weed in the same family!