Lowenstein's work on the pupil is well known in this country and in Europe.
It constituted, however, only one of many of his fields of interest. In al
l of them his contributions were based on experiments in which accurate, ob
jective recording replaced mere observation with the unaided eye. The resul
ting traces, obtained under stable conditions and with well-defined stimuli
, revealed specific normal or pathologic reaction patterns, and these, in t
urn, allowed recognition, quantification and localization of the underlying
physiologic mechanisms or pathologic defects.
During the early decades of this century Lowenstein invented and built his
own instruments. And as more advanced technical means became available, he
adopted these, so that his methods became more elegant and less time-consum
ing. This history forms an interesting parallel to the development of work
done by others throughout the twentieth century.