Which preposition to use with pharmaceutist

in Occurrences 1%

In 1883 Mr. Hekmeyer, pharmaceutist in chief of the Dutch Indies, exhibited at Amsterdam some specimens of Javanese edible earth, both in a natural state and in the form of various natural objects.

with Occurrences 1%

but it had cost him repeated efforts to reach this unassailable ground and more than one pharmaceutist with whom he abode as assistant had felt it a measure of prudence to dispense with his services.

Which preposition to use with  pharmaceutist