as for man the distance between his loins and the front of his body is much less than that between his sides so the distance between his back and his front is too short for the penis to disappear in it. the spread of the penis is because of what penetrates his veins nerves and ligaments of the lustful spirit and the winds that are in the veins and many animal spirits. and because of the penetration of this spirit into it much arterial blood penetrates into it for this spirit is not without the accompaniment of arterial blood and because of the abundance of blood and the abundance of spirits it is exposed to becoming very hot. the words of the book are selfexplanatory. and allah is the grantor of success.
وأما في الإنسان فإن المسافة بين صلبه ومقدم بدنه أقل كثيرا مما بين جانبيه فتقصر مسافة ما بين خلفه وقدامه عن اختفاء القضيب فيها، وانتشار القضيب هو لأجل ما ينفذ في عروقه وأعصابه وأربطته من الروح الشهو أني والرياح التي تكون في العروق وأرواح كثيرة حيوانية، ولأجل نفوذ هذه الروح إليه ينفذ فيه دم كثر شرياني فإن هذه لروح لا تخلو عن مصاحبة الدم الشرياني لها ولأجل كثرة الدم وكثرة الأرواح يعرض له أن يسخن كثيرا. وألفاظ الكتاب غنية عن الشرح. والله ولي التوفيق.