Simplify the following text for a Grade 11 native English-speaking person.
Original: From 1854 to 1862 , age 31 to 39 , Wallace traveled through the Malay Archipelago or East Indies ( now Malaysia and Indonesia ) , to collect specimens for sale and to study nature .
Simplified: From 1854 to 1862 , age 31 to 39 , Wallace traveled through the Dutch East Indies ( now Malaysia and Indonesia ) , to collect specimens for sale and to study nature .