凡是物体遇到火就会燃烧，但火浣布、凤首木等，唯独不怕火烧而不焦黑；另外火油遇到水火焰反而更旺盛，钱武肃王曾经使用过（火油）。
龙蜕骨，蛇蜕皮，麋鹿和鹿脱落角，螃蟹脱螯，人则更换牙齿，这是自然的气化现象。
（炳章）按语：物理事物的变化，往往有难以用常理理解的情况，比如鲨鱼变成鹿，由鱼类变为兽类；又如田鼠化为蝙蝠（注：原文此处似有缺漏或异文，通常指“田鼠化为鹌”或类似说法，但依原文直译），气血衰弱则须发容易变白，常常在此处验证寿命的长短。我观察《晋书》中王彪之的传记说：他二十岁时，胡须和头发已经全白，当时的人称他为“王白须”，但他官至光禄大夫，仪同三司，去世时七十三岁。这大概是特殊的禀赋，不可以用常情来推测。又比如宋朝的杜祁公杜衍，年纪超过四十岁，胡须和头发全部变白，去世时八十岁。
（炳章）按语：少年时期勤奋学习，以及操劳过度，导致血气耗伤，就会须发早白，这是因为营养不足，色素不能滋养须发。如果胡须和头发像钟一样，清亮而且长，这就是所谓的“童颜鹤发”，是长寿富贵的征兆，就像晋朝的王彪之、宋朝的杜祁公杜衍这一类人吧。
All things burn when exposed to fire, yet Huawan cloth (fire-washing cloth) and Fengshou wood are unique in that they do not char when burned. Furthermore, Huoyou (fire oil) burns more intensely when it comes into contact with water; Qian Wusu Wang once used this substance.
Dragons shed their bones, snakes shed their skins, elk and deer shed their antlers, crabs shed their claws, and humans replace their teeth; this is the natural transformation of Qi (vital energy).
(Bingzhang) Note: The changes in physical phenomena are often difficult to explain by common sense. For example, sharks transforming into deer, changing from fish to beasts; or field mice transforming into [birds/bats - text implies transformation]. When Qi and Blood decline, hair and beard turn white easily; this serves as an indicator of lifespan. I observed in the biography of Wang Biaozhi in the *Book of Jin* that at the age of twenty, his beard and hair were already completely white. People of the time called him "Wang White-Beard," yet he rose to the rank of Guanglu Dafu (Grand Master of the Palace) and Yi Tong San Si (Official equivalent to the Three Excellencies), dying at the age of seventy-three. This is likely a special endowment and cannot be judged by ordinary standards. Similarly, Du Yanzhou (Du Qi Gong) of the Song Dynasty had completely white hair and beard after the age of forty, living to be eighty years old.
(Bingzhang) Note: Diligent study in youth and excessive labor consume Qi and Blood, leading to premature whitening of hair and beard. This is due to insufficient nutrition, causing pigments to fail to nourish the hair and beard. If the beard and hair are clear, long, and lustrous, as seen in the phrase "childlike face and crane-like hair" (Tongyan Hefa), it is a sign of longevity and wealth, such as in the cases of Wang Biaozhi of the Jin Dynasty and Du Yanzhou of the Song Dynasty.