脉之难明古今所病也至虚有盛候大实有羸状疑似之间便有死生之异士大夫多秘所患以求
痊验
医能否使索病于冥漠之中辩虚实冷热于疑似之间医者不幸而失终不肯自谓失也巧饰遂非以全
其名间有谨愿者虽合主人之言亦参以所见两存而杂治吾平生求医盖于平时默验其工拙有疾求
疗必尽告以所患使医了然知患之所在然后诊之虚实冷热先定于中脉之疑似不能惑也故虽
中医治吾疾常愈吾求疾愈而已岂以困医为事哉(东坡)
甄权以母疾与弟立言究习方书遂为高医所撰脉经针方明堂等图传于时后以医显义兴许胤
宗或
劝其着书贻后世答曰医特意耳思虑精则得之脉之候幽而难明吾意所解口不能宣也古之上医要
在视脉病乃可识病与药值唯用一物攻之气纯而愈速今之人不善为脉以情度病多其物以幸其功
譬猎不知兔广络
原野冀一人获之术亦疏矣一药偶得它味相制弗能专力此难愈之验也脉之妙处不可传虚着方
剂终无益于世此吾所以不着书也(唐书本传)
观比闻公以眼疾饵黄连至十数两犹不已不知果然否审如所闻殆不可也观顷年血气未定颇
好方
术之说读医经数年尝记释者云服黄连苦参久而反热甚以为不然后乃信之盖五味入胃各归其所
喜故酸先归心甘先归脾辛先归肺咸先归肾入肝则为温入心则为热入肺则为清入肾则为寒入肝
则为至阴而血气兼之皆为增其气不已脏气有所偏胜则必有所偏绝黄连苦参性虽大寒然其味至
苦入胃则先归于心久而不已则心火之胜火则热乃其理也眼疾之生本于肝之热肝与心为子母夫
心为子肝为母心火也肝亦火也肾孤脏也人尝患一水不胜二火今病本于肝而久饵苦药使心有所
偏胜是所谓以火救火命之曰益多其不可亦明矣夫药所以疗疾其过也适所以为疾比闻初作时十
已损其七八正宜节药慎护饮食以俟其自平非如决疣溃痈可以忽然一朝去也辄
具以进惟留意而听之无忽(秦观与乔希圣论黄连书)
脉象的难以明了，是古往今来都存在的弊病。极度虚弱的病症可能表现出强盛的征候，极度实邪的病症可能表现出羸弱的形态，在疑似之间便有着生死攸关的差异。士大夫阶层大多隐瞒自己的病患，以求验证医生的疗效。
医生能否使（患者）在冥漠难辨之中找到病因，在虚实冷热的疑似之间做出辨别？如果医生不幸诊断失误，最终也绝不肯承认自己失误，而是巧言饰非，以保全自己的名声。间或有谨慎忠厚的人，虽然顺从主人的话，也会参杂进自己的见解，两种方法混杂治疗。我平生求医，往往在平时默默观察其医术的高下；一旦患病求治，必定将所患之症毫无保留地告知医生，使医生了然知晓病灶所在，然后再进行诊察。这样，虚实冷热在心中先有定见，脉象的疑似之处便不能迷惑医生。因此，即使是普通的中医，治疗我的疾病也常常痊愈。我所求的只是疾病痊愈，哪里会把难为医生当作事情呢？（苏轼语）
甄权因为母亲的疾病，与弟弟甄立言研究研习方书，于是成为高明的医生。他撰写了《脉经》、《针方明堂》等图籍，流传于当时，后来凭借医术显名。义兴人许胤宗，有人劝他著书留给后世，他回答说：“医学只是意会罢了，思虑精专就能领悟。脉象的候验幽深而难以明了，我心中所理解的，口不能表达出来。”古代的上等医生，关键在于通过视诊和切脉来认识疾病，然后才可以识别病情。用药与病情相契合，只用一味药来攻治病邪，药气纯正，痊愈就迅速。现在的人不善于诊脉，凭主观推测病情，增加药物种类以侥幸获得成功，这就像打猎却不知道兔子在哪里，广泛地覆盖原野，希望有一人捕获它，这种办法也太疏漏了。一味药偶然有效，其他味道相互制约，不能专一用力，这是难以痊愈的验证。脉学的妙处不可传授，随意开具方剂最终对世人没有益处，这就是我所以不著书的原因。（据《旧唐书·甄权传》）
我近来听说您因眼疾服用黄连，多达十几两，仍然不停止，不知是否确实？如果像传闻那样，恐怕是不可以的。我前几年血气未定，颇喜好方术之说，研读医经数年，曾记得佛家典籍中说：长期服用黄连、苦参，反而会产生热症，起初我不相信，后来才相信。大概五味入胃，各自归于其所喜好的脏腑。酸味先归心，甘味先归脾，辛味先归肺，咸味先归肾，入肝则为温，入心则为热，入肺则为清，入肾则为寒。入肝则属于至阴，而血气兼之，都是增加其气，不停止的话，脏气就会有偏胜，那么必然有所偏绝。黄连、苦参性虽大寒，但其味极苦，入胃后先归于心，长久不停止，就会导致心火偏胜，火胜则热，这就是其中的道理。眼疾的产生，本源于肝热。肝与心是子母关系，心为子，肝为母，心属火，肝亦属火。肾是孤脏，人常患“一水不胜二火”的情况。如今病本源于肝，又长期服用苦药，使心有所偏胜，这就是所谓的“以火救火”，称之为“益多其不可”，也是显而易见的了。药物是用来治疗疾病的，如果使用过度，恰好就成为疾病。我听说刚发病时，身体已经损耗了七八分，正应该节制用药，谨慎护理饮食，以等待其自行平复，不像决疣溃痈可以忽然一朝去除。特此陈述以上意见，希望您留意并听取，不要忽视。（秦观《与乔希圣论黄连书》）
The difficulty in understanding pulse diagnoses has been a problem since ancient times. Extreme deficiency may present with excess symptoms, and extreme excess may present with deficient signs; between these ambiguous presentations lie the differences of life and death. Scholars often conceal their ailments to verify the efficacy of physicians.
Can a physician locate the disease amidst obscurity and distinguish between deficiency/excess and cold/heat in ambiguous situations? If a physician unfortunately makes a mistake, they are ultimately unwilling to admit it, instead using clever excuses to cover up faults and preserve their reputation. Occasionally, there are cautious and honest practitioners who, while complying with the patient's words, also incorporate their own observations, treating with a mixture of both approaches. In my lifelong experience of seeking medical care, I usually silently observe their competence beforehand. When ill and seeking treatment, I must inform the physician completely of my symptoms so that they clearly understand the location of the disease before taking the pulse. Thus, the patterns of deficiency/excess and cold/heat are determined in my mind beforehand, and the ambiguities of the pulse cannot confuse them. Therefore, even an ordinary *Zhongyi* (Traditional Chinese Medicine practitioner) can often cure my illness. I only seek the cure of my illness; why would I make things difficult for the physician? (Su Shi)
Zhen Quan, due to his mother's illness, studied and practiced medical formulas with his brother Zhen Lizhan, becoming a highly skilled physician. He compiled diagrams such as *Mai Jing* (Pulse Classic) and *Zhen Fang Ming Tang* (Needle Methods and Acupoint Diagrams), which were circulated at the time, and later gained prominence through his medical practice. Xu Yinzong of Yixing was advised by some to write books for posterity. He replied: "Medicine is merely a matter of intuitive understanding; precise contemplation leads to mastery. The manifestations of the pulse are profound and difficult to clarify; what I understand intuitively, I cannot fully express in words." Ancient superior physicians relied primarily on observation and pulse diagnosis to recognize diseases, and only then could they identify the condition. When the medication matches the disease, using a single herb to attack the pathogen ensures pure medicinal qi and faster recovery. People today are not good at pulse diagnosis; they guess the disease based on subjective feelings and use multiple substances to hope for success. This is like hunting without knowing where the rabbit is, covering vast fields in the hope that someone might catch one—a very inefficient method. If one herb happens to work but other flavors counteract it, preventing focused effort, this is evidence of difficulty in curing. The subtleties of pulse diagnosis cannot be transmitted; arbitrarily prescribing formulas ultimately benefits no one. This is why I do not write books. (According to *Old Book of Tang - Biography of Zhen Quan*)
I recently heard that you took *Huanglian* (Coptidis Rhizoma) for your eye disease, consuming over ten *liang*, yet still did not stop. I wonder if this is true? If it is as reported, it is likely inadvisable. In my younger years, when my blood and qi were not yet settled, I was quite fond of theories regarding prescriptions. After studying medical classics for several years, I once recalled a Buddhist text stating: "Long-term consumption of *Huanglian* (Coptidis Rhizoma) and *Kushen* (Sophorae Flavescentis Radix) may eventually lead to heat sensations." At first, I did not believe it, but later I came to accept it. Generally, the five flavors enter the stomach and return to their preferred organs: sourness first returns to the Heart, sweetness to the Spleen, pungency to the Lung, saltiness to the Kidney. Entering the Liver, it becomes warm; entering the Heart, it becomes hot; entering the Lung, it becomes clear; entering the Kidney, it becomes cold. Entering the Liver belongs to extreme Yin, combined with blood and qi, all increasing its qi. If unceasing, the organ qi will become excessive, leading to imbalance. Although *Huanglian* and *Kushen* have a great cold nature, their taste is extremely bitter. Upon entering the stomach, they first return to the Heart. If taken for a long time without stopping, it causes excessive Heart Fire. Fire exceeding leads to heat; this is the principle. Eye diseases originate from Liver Heat. The Liver and Heart are in a mother-son relationship; the Heart is the son, the Liver is the mother. The Heart is Fire, and the Liver is also Fire. The Kidney is a solitary organ. Humans often suffer from "one water failing to overcome two fires." Now, the disease originates in the Liver, and long-term consumption of bitter medicines causes the Heart to become excessive. This is what is called "using fire to save fire," termed "increasing the excess," which is obviously inadvisable. Medicines are used to treat diseases; if used excessively, they themselves become the disease. I heard that when the illness first started, your health had already been damaged by seven or eight parts. You should properly restrict medication and carefully protect your diet, waiting for self-recovery, rather than expecting sudden removal like bursting a boil. I hereby submit these thoughts; please pay attention and listen, do not neglect them. (Qin Guan, "Letter to Qiao Xisheng on Huanglian")