药局中所鬻坎离砂，沃之以醋自能发热，以熨受寒腿疼及臂疼，颇有效验，而医者犹多不知其所以然
之故。究其实际，不外物质化合之理也。按此砂纯系用铁屑制成。其制法将铁屑 红，即以醋喷灭之，晾
干收贮。用时复以醋拌湿，即能生热。盖火非养气不着，当铁屑 红之时，铁屑中原具有养气，经醋喷灭，其
养气即永留铁中。况养气为酸素，醋味至酸，其含养气颇多，以之喷灭 红之铁，醋中之养气亦尽归铁中。
用时再沃之以醋，其从前所蕴之养气，遂感通发动而生热。以熨因寒痹疼之处，不惟
可以驱逐凝寒，更可流通血脉，以人之血脉得养气则赤，而血脉之瘀者可化也。
敝邑多红荆，而县北泊庄尤多，各地阡塍皆有荆丛绕护。乙巳季春，牛多瘟死，剥牛者弃其脏腑，但食
其肉，未闻有中毒者。独泊庄因食牛肉，同时中毒者二百余人，迎愚为之解救，既至（相距七里许）死者已
三人矣。中毒之现象∶发热、恶心、瞑眩、脉象紧数。投以黄连、甘草、金银花、天花粉诸药，皆随手
奏效。细询其中毒之由，缘洗牛肉于溪中，其溪中多浸荆条，水色变红，洗后复晾于荆条闸极上，至煮肉
时又以荆为薪，及鬻此肉，食者皆病，食多则病剧，食少则病轻耳。愚闻此言，因恍忆“老牛
反荆花”原系邑中相传古语，想邑中古人必有中此毒者，是以其语至今留诒，人多知之。特其事未经见，虽
知之亦淡然若忘耳。然其相反之理，究系何因，须俟深于化学人研究也。因又忆曩时阅小说，见有田家妇 于
田间，行荆芥中，以 之饭有牛肉，食者遂中毒。疑荆芥即系红荆之讹，不然岂牛肉反荆花，而又反荆
芥耶？医界诸大雅，有能确知之者，又期不吝指教。
药局中出售的坎离砂，浇上醋后自然能发热，用它熨烫受寒引起的腿疼和臂疼，非常有效，但医生们大多不知道其中的原理。探究其实际，不外乎是物质化合的道理。据观察，这种砂完全是用铁屑制成的。它的制作方法是：将铁屑烧红，立即用醋喷洒使其熄灭，晾干后收藏备用。使用时再用醋拌湿，就能产生热量。大概因为火需要氧气才能燃烧，当铁屑烧红时，铁屑中原有的氧气，经过醋喷洒熄灭后，便永久地保留在铁中。况且氧气即酸素，醋味极酸，含有大量的氧气，用醋喷洒烧红的铁，醋中的氧气也全部归于铁中。使用时再浇上醋，铁中先前蕴藏的氧气，于是感应发动而产生热量。用它熨烫因寒痹疼痛的部位，不仅可以驱逐凝结的寒气，更能流通血脉，因为人的血脉得到氧气就会变红，而血脉中的瘀滞也可以化解。
我家乡多生红荆（一种植物），县北的泊庄尤其多，各地的田间小路都有荆丛环绕保护。乙巳年暮春时节，牛群多因瘟疫死亡，剥牛的人丢弃了牛的脏腑，只吃牛肉，没听说有人中毒。唯独泊庄因为食用牛肉，同时中毒者达二百多人，请我去解救。等我赶到（相距七里左右）时，已有三人死亡。中毒的现象表现为：发热、恶心、头晕目眩、脉象紧数。投用黄连、甘草、金银花、天花粉等药物，都立刻见效。仔细询问其中毒的原因，是因为在溪水中清洗牛肉，溪水中浸泡着许多荆条，水色变红，洗完后又晾在荆条闸极上，等到煮肉时又把荆条当作柴火，以及售卖这些肉，吃了的人都生病了，吃得多吃病重，吃得少则病轻。我听到这话，忽然想起“老牛反荆花”原是家乡相传的古语，猜想家乡的古人一定有中毒于此的，所以这句话流传至今，人们都知道。只是这件事未曾亲眼见过，虽然知道也淡然得快要忘记了。然而这相反的原理，究竞是什么原因，必须等待精通化学的人来研究。因此又回忆起从前读小说时，看到有农家妇女在田间，行走在荆芥丛中，把荆芥混入饭中有牛肉的食物中，吃的人就中毒了。怀疑荆芥就是红荆的讹误，不然难道是牛肉既反荆花，又反荆芥吗？医学界的各位高雅之士，如果有确知其中原委的，希望不吝赐教。
The *Kanli Sha* (Caini Sand) sold in pharmacies generates heat spontaneously when vinegar is poured on it. Applying it with moxibustion-like warming to leg and arm pain caused by cold exposure is quite effective, yet many physicians are unaware of the underlying reason. Upon investigation, this phenomenon essentially boils down to the principles of chemical combination. This sand is composed entirely of iron filings. Its preparation method involves heating the iron filings until red-hot, then extinguishing them by spraying vinegar, followed by drying and storage. When used again, mixing with vinegar causes it to generate heat. This is because fire requires oxygen (*Yangqi*, 养气) to burn; when the iron filings are red-hot, they contain oxygen within them. After being extinguished by vinegar, this oxygen remains permanently bound within the iron. Furthermore, oxygen is an acid element, and vinegar is extremely sour, containing abundant oxygen. Spraying vinegar onto red-hot iron transfers the oxygen from the vinegar into the iron as well. When vinegar is poured on it during use, the previously stored oxygen is activated and released, generating heat. Applying this to areas painful due to cold-bi syndrome not only expels congealed cold but also promotes blood circulation, as human blood vessels turn red upon receiving oxygen, thereby resolving blood stasis.
Red Jing (a type of plant, likely *Rhus chinensis* or similar tannin-rich shrub) is abundant in my hometown, particularly in Bozhuang north of the county, where thickets surround field paths everywhere. In the late spring of the Yisi year, many cattle died of plague. Butchers discarded the viscera and consumed only the meat, with no reports of poisoning. However, in Bozhuang, over two hundred people simultaneously fell ill after eating beef, prompting me to be summoned for rescue. By the time I arrived (approximately three kilometers away), three had already died. The symptoms of poisoning included fever, nausea, dizziness/confusion, and a tight, rapid pulse. Administration of *Huanglian* (Coptis Rhizome), *Gancao* (Licorice Root), *Jinyinhua* (Honeysuckle Flower), and *Tianhuafen* (Trichosanthes Root) proved immediately effective. Detailed inquiry revealed the cause: the beef was washed in a stream where many Jing branches were steeping, turning the water red. It was then dried on a rack made of Jing branches, and later cooked using Jing branches as firewood. Those who bought and ate this meat became ill; those who ate more suffered severe illness, while those who ate less had mild symptoms. Hearing this, I suddenly recalled the local proverb "Old cow reacts with Jing flowers," which has been passed down through generations. I surmised that ancestors in our region must have suffered from this poisoning, hence the saying persists. Although few have witnessed it personally, leading to its gradual obscurity, the exact mechanism behind this antagonism awaits study by experts in chemistry. I also recalled reading a novel describing a rural woman walking through *Jingjie* (Schizonepeta Herb) fields, mixing it with rice containing beef, resulting in poisoning for the eater. I suspect "Jingjie" might be a misnomer for "Red Jing." Otherwise, how could beef react with both Jing flowers and Jingjie? I hope learned physicians among you can clarify this matter and offer guidance without reservation.