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they so closely followed both in time and as disciples. But 
it is requisite to distinguish those of the Greek authors, as 
Actuarins and Myrepsus, who wrote in the twelfth and 
thirteenth centuries, and were therefore subsequent to the 
chief of the Arabs ; to whom it would not be difficult to 
prove they are largely indebted for their improved Materia 
Medica and Pharmacy. From these we ascend readily to 
Paulus -Egineta, who wrote at the beginning of the seventh 
century, and thence to Alexander Trallianus in the sixth, 
yEtius in the fifth, and from him to Oribasius, who wrote 
in the fourth century. Many of these are usually despised 
as being mere compilers ; but besides the actual additions 
that some of them made to the science, the production of 
their works before the invention of printing must have been 
positively useful in more extensively diffusing the science of 
their more able predecessors. But as studying Materia 
Medica, and anxious to trace the history of a drug from 
recent to ancient times, or vice versa, we shall not com- 
plain of their compilations, except when they are imperfect, 
since they but serve to connect more closely the several links 
of the chain of authors, which extends from ancient to 
modern times. 
Glancing for an instant at the continued existence of the 
Alexandrian School, from the times of Erasistratus and 
Herophilus, 300 years before the Christian era, to that of 
the Arabs, as accounting for the frequent appearance of 
Egyptian remedies among the articles of Materia Medica: 
we should next trace the Greek authors from Oribasius to 
Galen in the second century, and from him to Dioscorides, 
the most copious author on the Materia Medica of the 
ancients. He probably lived in the first century, as he is 
frequently quoted by Galen, and may therefore have been a 
contemporary of Pliny ; from whom, as well as Celsus, we 
obtain a knowledge of the Materia Medica and Pharmacy 
