There he studied medicine and botany under Herman Boerhaave and Adriaan van Royen, and became the intimate friend of Linnaeus, whom he several times assisted with gifts of money.
Three weeks later he traveled on to Sankt Andreasberg, sending samples of his collected minerals to Hieronymus David Gaubius, Johann Andreas Cramer and Gronovius.
His further travels led him via Berlin and Halle to Leipzig, where he met Johann Ernst Hebenstreit and Christian Gottlieb Ludwig.
When he arrived in Karlsbad, he realized that his plans to travel to Prague, Vienna and Hungary were no longer realistic, and thus decided to return to England via Flanders and Holland.
Another Isaac Lawson, possibly a son, entered Leyden University 13 March 1747, and is described in the register as Britanno-Edinburgensis.