During a short trip to Puerto Rico, at the request of Jesuit fathers to offer assistance in the creation of a zoological collection in 1868, when revolutionary activities were beginning in Cuba as well as Puerto Rico, he met with don Tomás Blanco, according to naturalist Dr. Agustín Stahl.

This institute was closed several months later, in keeping with the Spanish government's policy expressed to the bishops of Santiago de Cuba and of San Juan of limiting the opportunities for higher learning on both islands.

He subsequently travelled from Havana to Puerto Rico's west coast aboard the "Marsella" in September 1875.

He remained in Puerto Rico for approximately one year; while he was there, he changed his name from Johannes Christoph to its Spanish equivalent, Juan Cristóbal.

[1] In 1986, on the 90th anniversary of his death, Cuba issued a series of postal stamps commemorating Gundlach.