''De Gradibus'' was an

Arabic Arabic (, ' ; , ' or ) is a Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C. E.Watson; Walter ...

book published by the Arab physician

Al-Kindi Abū Yūsuf Yaʻqūb ibn ʼIsḥāq aṣ-Ṣabbāḥ al-Kindī (; ar, أبو يوسف يعقوب بن إسحاق الصبّاح الكندي; la, Alkindus; c. 801–873 AD) was an Arab Muslim philosopher, polymath, mathematician, physician ...

(c. 801–873 CE). ''De gradibus'' is the Latinized name of the book. An alternative name for the book was ''Quia Primos''.p. 19
"Al-Kindi, A Precursor Of The Scientific Revolution"
Plinio Prioreschi, ''Journal of the International Society for the History of Islamic Medicine'' 1, #2 (October 2002), pp. 17–19. In ''De Gradibus'', Al-Kindi attempts to apply

mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...

pharmacology Pharmacology is a branch of medicine, biology and pharmaceutical sciences concerned with drug or medication action, where a drug may be defined as any artificial, natural, or endogenous (from within the body) molecule which exerts a biochemica ...

by quantifying the strength of drugs. According to Prioreschi, this was the first attempt at serious quantification in medicine.p. 18, Prioreschi 2002. He also developed a system, based on the phases of the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

, that would allow a doctor to determine in advance the most critical days of a

patient A patient is any recipient of health care services that are performed by healthcare professionals. The patient is most often ill or injured and in need of treatment by a physician, nurse, optometrist, dentist, veterinarian, or other heal ...

illness A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...

.(incomplete citation) Klein-Franke, p. 172 During the Arabic-Latin translation movement of the 12th century, ''De Gradibus'' was translated into

Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...

Gerard of Cremona Gerard of Cremona (Latin: ''Gerardus Cremonensis''; c. 1114 – 1187) was an Italian translator of scientific books from Arabic into Latin. He worked in Toledo, Kingdom of Castile and obtained the Arabic books in the libraries at Toledo. Some of ...

. Al-Kindi's mathematical reasoning was complex and hard to follow;

Roger Bacon Roger Bacon (; la, Rogerus or ', also '' Rogerus''; ), also known by the scholastic accolade ''Doctor Mirabilis'', was a medieval English philosopher and Franciscan friar who placed considerable emphasis on the study of nature through emp ...

commented that his method of computing the strength of a drug was extremely difficult to use.

References

Medical works of the medieval Islamic world Mathematical works of the medieval Islamic world Scientific works of the Abbasid Caliphate 9th-century Arabic books {{med-book-stub