金钗石斛，味甘、微苦，性微寒，无毒。不可用竹斛、木斛，用之无功，石斛却惊定志，
益
精强阴，尤能健脚膝之力，善起痹病，降阴虚之火，大有殊功。今世吴下之医，颇喜用之，
而天下人尚不悉知其功用也。盖金钗石斛，生于粤闽岩洞之中
，岩洞乃至阴之地，而粤闽又至阳之方也，秉阴阳之气以生，故寒不为寒，而又能降虚浮之
热。夫虚火，相火也，相火宜补，而不宜泻。金钗石斛妙是寒药，而又有补性，且其性又下
行，而不上行。若相火则易升，而不易降者也，得石斛则降而不升矣。夏月之间，两足无力
者，服石斛则有力，岂非下降而兼补至阴之明验乎。故用黄柏、知母泻相火者，何如用金钗
石斛之为当乎。盖黄柏、知母泻中无补，而金钗石斛补中有泻也。
或问金钗石斛降阴虚之火，乃泻阴之物也，何以能健脚膝之力，其中妙义，尚未畅发。
曰∶
肾有补而无泻，何以金钗石斛泻肾，而反补肾，宜子之疑也。余上文虽已略言之，而今犹当
罄言之。夫肾中有水、火之分，水之不足，火之有余也；火之有余，水之不足也。是水火不
能两平者，久矣。脚膝之无力者，肾水之不足也。水不足则火觉有余，火有余则水又不足，
不能制火矣。不能制火，则火旺而熬干骨中之髓，欲其脚膝之有力也。必不得之数矣。金钗
石斛，本非益精强阴之药，乃降肾中命门虚火之药也，去火之有余，自然益水之不足，泻肾
中之虚火，自然添骨中之真水矣，故曰∶强阴而益精。此脚膝之所以健也。然则黄柏、知母
亦泻肾火之药，何以不能健脚膝？不知肾中之火，大寒则泻而不补，微寒则补而能泻。此金
钗石斛妙在微寒，以泻为补也。（〔批〕相火者，虚火也，虚火必补而后息。石斛之补肾，
岂
及熟地，然以轻虚之体，潜入于命门阴火之中，能引入命门之火，仍归于肾，舍石斛更无他
药可代。大寒之药，有泻而无补；微寒之药，有补而无泻，发前人所未发。）
或问子恶用黄柏、知母之泻火，何又称金钗石斛？不知金钗石斛，非知母、黄柏可比。
知母
、黄柏大寒，直入于至阴，使寒入于骨髓之中。金钗石斛不过微寒，虽入于至阴，使寒出于
骨髓之外，各有分别也。
或疑金钗石斛使寒出于骨髓，实发前人之未发，但无征难信耳。曰∶石斛微寒，自不伤
骨，
骨既不伤，则骨中之热自解，骨中热解，必散于外，此理之所必然，不必有征而后信也。
金钗石斛，味道甘、微苦，性质微寒，无毒。不可使用竹斛、木斛，使用它们没有功效。石斛能镇惊安神，补益精髓、强壮阴气，尤其具有强健脚膝的力量，善于治愈痹病，降低阴虚产生的虚火，有极大的特殊功效。当今吴地（江浙一带）的医生，很喜欢使用它，但天下人还不完全了解它的作用。大概金钗石斛，生长在广东、福建的岩洞之中，岩洞是极阴的地方，而广东、福建又是极阳的区域，它禀受阴阳之气而生，所以其寒性不至于过寒，又能降低虚浮的热邪。所谓虚火，就是相火，相火适宜用补法，而不适宜用泻法。金钗石斛妙在虽然是寒药，却又有补性，而且它的药性是下行而不是上行。像相火则是容易上升、不容易下降的，得到石斛就能使其下降而不升腾。夏季之间，两脚无力的人，服用石斛后就会有力，这难道不是它既能下降又能补益至阴的明显证据吗？所以，使用黄柏、知母来泻相火，哪里比得上使用金钗石斛恰当呢？大概黄柏、知母在泻火中没有补益作用，而金钗石斛在补益中兼有泻火作用。
有人问：金钗石斛降低阴虚之火，是泻阴的药物，为什么还能强健脚膝的力量？其中的奥妙，还没有充分阐发。回答说：肾脏只有补法而没有泻法，为什么金钗石斛泻肾，反而补肾？这是你应该怀疑的地方。我上文虽然已经略微提到，但现在应当详尽说明。肾中有水和火的区分，水不足，则火有余；火有余，则水不足。水火不能平衡的情况，已经很久了。脚膝无力的原因，是肾水不足。水不足则感觉火有余，火有余则水更加不足，无法制约火了。无法制约火，则火旺而熬干骨中的髓液，想要脚膝有力，是不可能的事情。金钗石斛，本来不是直接补益精髓、强壮阴气的药物，而是降低肾中命门虚火的药物，去除有余的火，自然补充不足的阴水，泻去肾中的虚火，自然增添了骨中的真水，所以说：强阴而益精。这就是脚膝之所以健壮的原因。那么黄柏、知母也是泻肾火的药物，为什么不能强健脚膝？不知道肾中之火，大寒的药是只泻不补，微寒的药才是补而能泻。金钗石斛的妙处在于微寒，以泻为补。（〔批注〕相火，就是虚火，虚火必须通过补益才能平息。石斛补肾的效果，哪里比得上熟地黄？然而凭借它轻清虚灵的特性，潜入命门阴火之中，能将命门之火引入并回归于肾，除了石斛没有其他药物可以替代。大寒的药物，只有泻而没有补；微寒的药物，只有补而没有泻，这是前人未曾阐发的观点。）
有人问：你厌恶使用黄柏、知母来泻火，为什么又推崇金钗石斛？不知道金钗石斛，不能与知母、黄柏相比。知母、黄柏是大寒之药，直接进入至阴之地，使寒气深入骨髓之中。金钗石斛不过是微寒，虽然也进入至阴之地，却是将寒气从骨髓之外排出，二者各有分别。
有人怀疑金钗石斛能使寒气出于骨髓，确实是前人未发之论，但没有证据难以让人相信。回答说：石斛微寒，自然不会损伤骨骼，骨骼既然不受伤，那么骨中的热邪自然解除，骨中热邪解除，必然散发到体外，这是道理上必然的结果，不必有了证据才相信。
Jincha Shihu (Dendrobium nobile), with a sweet and slightly bitter taste, is of a slightly cold nature and non-toxic. It should not be confused with Zhuxu (Bamboo Dendrobium) or Muxu (Wood Dendrobium); using them yields no efficacy. Shihu can calm fright and stabilize the spirit, benefit essence and strengthen Yin, and particularly possesses the power to strengthen the feet and knees. It is excellent for treating Bi syndrome (obstruction syndrome characterized by pain, heaviness, or numbness), descending fire due to Yin deficiency, and holds great special merit. Physicians in the Wu region (Jiangsu and Zhejiang areas) nowadays favor its use, yet people throughout the world do not fully understand its functions. This is because Jincha Shihu grows in rock caves in Guangdong and Fujian. Rock caves are places of extreme Yin, while Guangdong and Fujian are regions of extreme Yang. Born from inheriting the Qi of both Yin and Yang, its cold nature is not excessively cold, and it can descend floating heat. The so-called deficient fire refers to Ministerial Fire (Xianghuo). Ministerial fire is suitable for tonification rather than purgation. The subtlety of Jincha Shihu lies in the fact that although it is a cold herb, it also has tonifying properties, and its action moves downward rather than upward. Ministerial fire tends to ascend easily but descend with difficulty; with Shihu, it descends and does not ascend. During summer, when one's legs feel weak, taking Shihu restores strength. Is this not clear evidence of its ability to descend and simultaneously tonify Extreme Yin? Therefore, using Huangbai (Phellodendron Bark) and Zhimu (Anemarrhena Rhizome) to purge Ministerial fire is far less appropriate than using Jincha Shihu. Huangbai and Zhimu purge without tonifying, whereas Jincha Shihu tonifies while purging.
One might ask: Since Jincha Shihu descends fire due to Yin deficiency, it is a substance that drains Yin. How can it then strengthen the power of the feet and knees? The profound meaning here has not been fully elucidated. I reply: The Kidney is subject only to tonification, never to purgation. Why does Jincha Shihu drain the Kidney yet conversely tonify it? Your doubt is understandable. Although I briefly mentioned this earlier, I shall now explain it thoroughly. Within the Kidney, there is a distinction between Water and Fire. Insufficiency of Water leads to excess Fire; excess Fire leads to insufficiency of Water. The inability of Water and Fire to remain in balance has long existed. Weakness in the feet and knees stems from an insufficiency of Kidney Water. When Water is insufficient, Fire feels excessive; when Fire is excessive, Water becomes even more insufficient, failing to control the Fire. If Fire cannot be controlled, it flares up and boils dry the marrow within the bones. Under such conditions, expecting strength in the feet and knees is impossible. Jincha Shihu is not originally a medicine for directly benefiting essence and strengthening Yin; rather, it is a medicine that descends the deficient fire of the Mingmen (Gate of Life) in the Kidney. By removing the excess Fire, it naturally supplements the insufficient Water. By draining the deficient fire in the Kidney, it naturally replenishes the true Water in the bones. Hence it is said to "strengthen Yin and benefit essence." This is why the feet and knees become strong. Then, since Huangbai and Zhimu are also medicines that drain Kidney Fire, why can they not strengthen the feet and knees? One must understand that for Kidney Fire, herbs of Great Cold nature purge without tonifying, whereas herbs of Slightly Cold nature tonify while purging. The subtlety of Jincha Shihu lies in its Slightly Cold nature, achieving tonification through purgation. [Commentary: Ministerial fire is deficient fire; deficient fire must be tonified to subside. The effect of Shihu in tonifying the Kidney does not compare to Shudi (Prepared Rehmannia Root). However,凭借其 light and empty nature, it penetrates into the Yin fire of the Mingmen, guiding the fire of the Mingmen back to the Kidney. No other herb can replace Shihu. Herbs of Great Cold nature have purgative effects but no tonifying effects; herbs of Slightly Cold nature have tonifying effects but no purgative effects. This insight was not previously developed.]
One might ask: You dislike the use of Huangbai and Zhimu for purging fire, so why do you praise Jincha Shihu? You do not realize that Jincha Shihu cannot be compared to Zhimu and Huangbai. Zhimu and Huangbai are of Great Cold nature, entering directly into Extreme Yin, causing cold to penetrate deep into the bone marrow. Jincha Shihu is merely Slightly Cold; although it enters Extreme Yin, it expels cold from outside the bone marrow. There is a distinct difference between them.
Some may suspect that Jincha Shihu expelling cold from the bone marrow is indeed a novel theory not previously expressed, but lacking evidence makes it hard to believe. I reply: Because Shihu is Slightly Cold, it naturally does not damage the bones. If the bones are not damaged, the heat within the bones naturally resolves. Once the heat in the bones resolves, it necessarily dissipates outward. This is logically inevitable and does not require empirical evidence to be believed.