Halakha
Mar Samuel was very modest in his associations with others, openly honoring any one from whom he had gained any knowledge (Bava Metzia 33a). He never obstinately insisted on his own opinion, but yielded as soon as he was convinced of being in error ('Eruvin 90a, b; Ḥul. 76b; Ber. 36a). He was friendly to all men, and declared: "It is forbidden to deceive any man, be he Jew or pagan" (Ḥul. 94a). "Before the throne of the Creator there is no difference between Jews and pagans, since there are many noble and virtuous among the latter" (Yer. R. H. i. 57a). He taught that the dignity of manhood should be respected even in the slave: the slave is given to the master only as a servant, and the master has no right to treat him with condescension or to insult him (Niddah 17a, 47a). Once, when a female slave had been taken away from Samuel and he had unexpectedly recovered her by paying a ransom, he felt obliged to liberate her because he had given up hope of recovering her (Giṭ. 38a).
Mar Samuel seems to have possessed a thorough knowledge of the science of medicine as it was known in his day; this is evident from many of his medical maxims and dietetic rules scattered through the Talmud. He energetically opposed the view then current, even in intelligent circles, that most diseases were due to the evil eye, declaring that the source of all disease must be sought in the noxious influence exercised by the air and the climate upon the human organism (B. M. 107b). He traced many diseases to lack of cleanliness (Shab. 133b), and others to disturbances of the regular mode of living (B. B. 146a). He claimed to possess cures for most diseases (B. M. 113b), and was especially skilful in treating the eye (B. M. 85b); he discovered an eye-salve which was known as the "ḳillurin of Mar Samuel," although he himself said that bathing the eyes with cold water in the morning and bathing hands and feet with warm water in the evening were better than all the eye-salves in the world (Shab. 78a, 108b). Samuel discovered also a number of the diseases of animals (Ḥul. 42b). He sometimes drew the figure of a palm branch as his signature (Yer. Giṭ. ix. 50d), although this was, perhaps, used by physicians generally at that time as a sign of their profession (Rapoport, "'Erek Millin," p. 17).
From the scattered references in the Talmud it is impossible to determine exactly Mar Samuel's proficiency in astronomy; but he knew how to solve many mathematics problems and how to explain many phenomena. He says himself: "Although I am as familiar with the courses of the stars as with the streets of Nehardea, I can not explain the nature or the movements of the comets" (Ber. 58b). Samuel devoted himself especially to that branch of applied astronomy that deals with calendric science, which he taught to his colleagues and pupils. His astronomical studies of the revolutions of the moon enabled him to predict the beginning of the month ("Rosh Chodesh") as it was determined in Palestine, and he claimed to be able to remove the necessity of celebrating double holy days in the Diaspora (R. H. 20b; comp. Rashi ad loc.). He also computed a Hebrew calendar for sixty years, which he subsequently sent to R. Johanan, the head of the Palestinian teachers, as a proof of his knowledge (Ḥul. 95b). He was called "Yarḥina'ah" or "Yarhinai" ("yeraḥ" = "month") because of this familiarity with calendric science and this ability to determine independently the beginning of the month (B. M. 85b). According to Krochmal ("He-Ḥaluẓ," i. 76), "Shoḳed," another name given to Samuel, means "astronomer" (Yer. Ket. iv. 28b); but Hoffmann's view that "Shoḳed" (for which Babli has "Shaḳud"; Ket. 43b) means "the watchful, diligent one," is more likely correct. This name is said to have been given to Samuel because, despite his medical and astronomic studies, he devoted himself to the study of the Law.
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