Yu HOKI’s research while affiliated with Kyoto University and other places

Various issues involving theoretical and practical dimensions of medicine have been studied by using the Cairo Genizah. However, there are few in-depth studies on medical education. This article focuses on the medieval Arabic ophthalmology textbook, Masāʾil wa-ajwiba fīʿilm ṣināʿat al-kuḥl (hereafter MI), written by Dāniyāl ibn Shuʿyā. This is a textbook that arranges ʿAlī ibn ʿĪsā’s Tadhkirat al-kaḥḥāllīn (hereafter TK) into the question-and-answer format. MI is a concise and comprehensive textbook that includes anatomy, physiology, diagnostics, therapeutics, and pharmacology. Whereas Ḥunayn ibn Isḥāq’s Masāʾil fī al-ʿayn is limited to theoretical knowledge, MI contains the total procedure from knowing nature of eye diseases to treatment, and enables readers to apply certain medicinal substances to specific situations. However, MI’s crucial defect is that it arranges treatment plans along one linear disease progression, and cut off many derivative plans. Schematic composition is the remarkable feature of MI. Dāniyāl ibn Shuʿyā adopted some medical categories, which had been recognized but left unused in earlier Arabic medical books, in order to present the content in the concise scheme. The content of MI basically follows that of TK; therefore, it does not contain remarkably new elements. However, since Dāniyāl ibn Shuʿyā arranged TK into the roughly fixed pattern, he occasionally had to fill omissions of TK with his original questions and answers. These new components were presumably referred to by later ophthalmologists such as Khalīfa ibn Abī al-Maḥāsin al-Ḥalabī.

This paper reveals the practice of compounding medicines from the perspective of medieval Arabic medical books and the Cairo Genizah, focusing on ophthalmology. Some researchers have argued that, due to the large number of new remedies added through experience and trade, physicians gradually became free from the classical four-quality theory. However, our study shows that a kind of logic can be discerned in compound medicines, and that this logic requires knowledge of the classical four-quality theory. The practical dimensions have been neglected because most Arabic materials do not say anything about it. Given this textual restriction, The Cairo Genizah is important for Arabic medical history, because it o ers abundant information about medical practices. Among medical fragments of the Cairo Genizah, we focused on the speci c genre, which we would call “notebooks.” The text found in notebooks is consisting of recipes for compound medicines. Quite often, the genizah notebooks contain original recipes that are not found in the medical books. These are thought to be clearer re ections of the actual practice in medieval Cairo. We took up treatments of conjunctivitis (ramad) and eruptions of the eyelids (jarab). Firstly, we explored several medical books, and summarized the descriptions that related to the treatments of these eye diseases. Secondly, turning to the genizah notebooks, we collected recipes for the eye medicines, listed all of the ingredients, and checked their qualities. Finally, taking the characteristics of each ingredient into consideration, we examined whether or not these recipes exhibited theoretical consistency. Through a close examination of these materials, we found that the ingredients in the notebook recipes are different from those in the medical books, although their temperaments fulfill the conditions required for particular treatments. The ophthalmologists might have recognized the required effects for certain eye diseases, and then chosen substances that met those requirements.

In Medieval Arabic medical texts, a specific property (khāṣṣa) is thought to be one of the effects of a medicine, and effective in a specific humor or organ. This property is mainly mentioned to explain two phenomena, purgative medicines' attraction of a certain humor and theriacas strengthening of human innate heat. Galen had advocated the theory that the faculty of attracting a specific material inheres in a medical substance as its nature (referred to as the theory of inherence). The same view can be seen in the texts of Islamic philosopher-physicians such as Ibn Sīnā (d. 1037). On the other hand, Ibn Rushd (d. 1198) perceived the defects of this theory and criticised it. This article examines his criticism of the theory of inherence in his discussions about purgative medicines and theriacas. Ibn Rushd says that using the theory of inheritance, we cannot explain the phenomenon that when someone takes more than one dose of purgative medicine, it attracts not only the specific humor, but all of the humors. He then proposes the alternative theory that the specific property originates in the proportions of the qualities in the attracting and the attracted materials. From this perspective, he insists that the object of attraction varies according to the amount of the heat in the medicine. As for theriaca, Ibn Rushd criticises the theory of inherence as seen in the writings of Ibn Sīnā Ibn Sīnā claims that theriaca's specific property is generated from its substance, i.e. the combination of form with matter, not the mixture of the four qualities. But according to Ibn Rushd, with this explanation, it is impossible to explain the body's various responses to theriaca. Therefore he maintains that one must explain its specific property in terms of the four qualities. To conclude, Ibn Rushd considers his theory to be more capable of explaining various phenomena than the theory of inherence is.