Ｗhy Soap Works?

At the molecular level, soap breaks things apart. At the level of society, it helps hold everything together.

為何肥皂有效？

以分子層次來說，肥皂會使物質分裂，然而以社會層面來說，它卻能有助於事物的團結。

Washing with soap and water is one of the key public health practices that can significantly slow the rate of a pandemic and limit the number of infections. Credit...Alex Welsh for The New York Times

用肥皂和水清洗是重要的公衛習慣之一，可以顯著降低大流行的速度並限制感染的數量。

                                                                                                                         《紐約時報》Alex Welsh

It probably began with an accident thousands of years ago. According to one legend, rain washed the fat and ash from frequent animal sacrifices into a nearby river, where they formed a lather with a remarkable ability to clean skin and clothes. Perhaps the inspiration had a vegetal origin in the frothy solutions produced by boiling or mashing certain plants. However it happened, the ancient discovery of soap altered human history. Although our ancestors could not have foreseen it, soap would ultimately become one of our most effective defenses against invisible pathogens.

這種說法可以追溯至幾千年前的一場意外事故。傳說，雨水將動物死亡後的脂肪以及灰燼沖進附近的河流，其產生的泡沫具有清潔肌膚與衣物的出色能力。也許這個靈感是來自於煮沸或搗碎某些植物產生的泡沫而衍生的。無論如何，這個古老的發現改變了人類的歷史，儘管我們的祖先無法預見，但是肥皂最終成為我們抵禦病原體最有效的防禦手段之一。

People typically think of soap as gentle and soothing, but from the perspective of microorganisms, it is often extremely destructive. A drop of ordinary soap diluted in water is sufficient to rupture and kill many types of bacteria and viruses, including the new coronavirus that is currently circling the globe. The secret to soap’s impressive might is its hybrid structure.

人們通常認為肥皂很溫和，但是從微生物的角度來看，它卻具有極強的破壞力。只要用水稀釋一滴普通的肥皂就可以破壞並殺死許多不同類型的細菌和病毒，也包括了目前正在全球大流行的新冠病毒。肥皂令人驚艷的秘訣在於其混合型的結構。

Soap is made of pin-shaped molecules, each of which has a hydrophilic head — it readily bonds with water — and a hydrophobic tail, which shuns water and prefers to link up with oils and fats. These molecules, when suspended in water, alternately float about as solitary units, interact with other molecules in the solution and assemble themselves into little bubbles called micelles, with heads pointing outward and tails tucked inside.

肥皂是由針狀分子組成，每個分子都具有一個親水性的頭部(很容易與水結合)，以及一個疏水性的尾部(避免與水接觸而傾向於和油脂連結)。這些分子懸浮在水中時，會以單獨的單位交替漂浮，與溶液中的其他分子交互作用，並組裝成稱為膠束的小氣泡，其頭部朝外，尾巴塞在裡面。

Some bacteria and viruses have lipid membranes that resemble double-layered micelles with two bands of hydrophobic tails sandwiched between two rings of hydrophilic heads. These membranes are studded with important proteins that allow viruses to infect cells and perform vital tasks that keep bacteria alive. Pathogens wrapped in lipid membranes include coronaviruses, H.I.V., the viruses that cause hepatitis B and C, herpes, Ebola, Zika, dengue, and numerous bacteria that attack the intestines and respiratory tract.

一些細菌和病毒具有脂質膜，類似於雙層膠束(兩條疏水性尾部夾在兩個親水性頭環之間)，這些膜上覆蓋著重要的蛋白質，這些蛋白質可以使病毒感染細胞並執行使細菌存活的重要任務。包裹在脂質膜上的病原體包括冠狀病毒，HIV，引起乙型和丙型肝炎的病毒，皰疹，伊波拉病毒，茲卡病毒，登革熱以及攻擊腸道和呼吸道的多種細菌。

When you wash your hands with soap and water, you surround any microorganisms on your skin with soap molecules. The hydrophobic tails of the free-floating soap molecules attempt to evade water; in the process, they wedge themselves into the lipid envelopes of certain microbes and viruses, prying them apart

當用肥皂和水洗手時，肥皂分子將皮膚上的所有微生物包裹起來。自由漂浮的肥皂分子的疏水性尾端試圖逃離水，在此過程中，它們會將自己擠入某些微生物和病毒的脂質包膜中，將它們撬開。

“They act like crowbars and destabilize the whole system,” said Prof. Pall Thordarson, acting head of chemistry at the University of New South Wales. Essential proteins spill from the ruptured membranes into the surrounding water, killing the bacteria and rendering the viruses useless.

澳大利亞新南威爾士大學的化學教授 帕利·托拉達森(Pall Thordarson)說：“它們的作用就像鐵撬一樣，破壞了整個系統的穩定性。” 必需蛋白質從破裂的外套膜溢出到周圍的水中，殺死細菌並使病毒變得沒有作用。

How Soap Works

肥皂如何發揮作用？

Washing with soap and water is an effective way to destroy and dislodge many microbes, including the new coronavirus. For more about the virus, see How Coronavirus Hijacks Your Cells.

用肥皂和水清洗是消滅和清除包括新冠狀病毒在內的許多微生物的有效方法。有關該病毒的更多信息，請參閱《冠狀病毒如何劫持您的細胞》

By Jonathan Corum and Ferris Jabr

In tandem, some soap molecules disrupt the chemical bonds that allow bacteria, viruses and grime to stick to surfaces, lifting them off the skin. Micelles can also form around particles of dirt and fragments of viruses and bacteria, suspending them in floating cages. When you rinse your hands, all the microorganisms that have been damaged, trapped and killed by soap molecules are washed away.

同時，一些肥皂分子破壞了化學鍵，使細菌，病毒和污垢附著在表面，將它們與肌膚分離。膠束還可以在灰塵顆粒以及病毒和細菌的碎片周圍形成，使它們好似被關在漂浮的籠子裡。洗手時，所有被肥皂分子破壞、捕獲和殺死的微生物都會被洗掉。

On the whole, hand sanitizers are not as reliable as soap. Sanitizers with at least 60 percent ethanol do act similarly, defeating bacteria and viruses by destabilizing their lipid membranes. But they cannot easily remove microorganisms from the skin. There are also viruses that do not depend on lipid membranes to infect cells, as well as bacteria that protect their delicate membranes with sturdy shields of protein and sugar. Examples include bacteria that can cause meningitis, pneumonia, diarrhea and skin infections, as well as the hepatitis A virus, poliovirus, rhinoviruses and adenoviruses (frequent causes of the common cold).

整體來說，洗手消毒液的效果不比肥皂好。乙醇含量至少60%的消毒液與肥皂的作用類似，可以透過破壞病毒的脂質膜來殺死細菌和病毒，但是他們不能輕易地去除肌膚上的微生物。而且也有不靠脂質膜而感染細胞的病毒，也有用堅固的蛋白質和糖當作保護層保護其脆弱膜的細菌；包括可以引起腦膜炎、肺炎、腹瀉和皮膚感染的細菌，以及甲型肝炎病毒、脊髓灰質炎病毒、鼻病毒和腺病毒(引起普通感冒的常見原因)。

These more resilient microbes are generally less susceptible to the chemical onslaught of ethanol and soap. But vigorous scrubbing with soap and water can still expunge these microbes from the skin, which is partly why hand-washing is more effective than sanitizer. Alcohol-based sanitizer is a good backup when soap and water are not accessible.

這些更具韌性的微生物通常不易受到乙醇和肥皂的化學衝擊，但是，用肥皂和水強力擦洗仍然可以清除皮膚上的這些微生物，這就是為什麼洗手比消毒液更有效的原因。但是在沒有肥皂與水時，含有酒精的消毒液會是很好的備用手段。

In an age of robotic surgery and gene therapy, it is all the more wondrous that a bit of soap in water, an ancient and fundamentally unaltered recipe, remains one of our most valuable medical interventions. Throughout the course of a day, we pick up all sorts of viruses and microorganisms from the objects and people in the environment. When we absentmindedly touch our eyes, nose and mouth — a habit, one study suggests, that recurs as often as every two and a half minutes — we offer potentially dangerous microbes a portal to our internal organs.

在如今擁有機器手術與基因療法時代，令人感到驚訝的是，在水中的一小塊肥皂(一種古老而且本質上完全沒有改變的配方)仍然是我們最有價值的醫學預防措施之一。一整天下來，我們從環境中的物體和人體上會獲取各種病毒與微生物，一項研究指出，我們每隔兩分半鐘就會不經意地觸摸我們的眼口鼻一次，這會導致潛在的病毒通往我們人體內部的器官。

As a foundation of everyday hygiene, hand-washing was broadly adopted relatively recently. In the 1840s Dr. Ignaz Semmelweis, a Hungarian physician, discovered that if doctors washed their hands, far fewer women died after childbirth. At the time, microbes were not widely recognized as vectors of disease, and many doctors ridiculed the notion that a lack of personal cleanliness could be responsible for their patients’ deaths. Ostracized by his colleagues, Dr. Semmelweis was eventually committed to an asylum, where he was severely beaten by guards and died from infected wounds.

洗手近來已經被廣泛採用作為維護日常衛生的基礎。在1840年代，匈牙利醫師伊格納茲·塞梅爾維斯（Ignaz Semmelweis）博士發現：如果醫生有洗手，那麼分娩後死亡的婦女人數將大幅減少。在當時，微生物尚未被廣泛認為是疾病的傳播媒介，因此許多醫生認為「醫生沒做清潔而導致患者死亡的說法」是無稽之談，爾後，Semmelweis博士被他的同事排斥，最終在避難所被警衛毆打而死於傷口感染。

Florence Nightingale, the English nurse and statistician, also promoted hand-washing in the mid-1800s, but it was not until the 1980s that the Centers for Disease Control and Prevention issued the world’s first nationally endorsed hand hygiene guidelines.

身為英國的護士與一名統計學家的佛羅倫薩·南丁格爾（Florence Nightingale），在1800年代中期也提倡洗手，但一直到1980年代，疾病管制與預防中心才發佈了世界上第一個全國認可的洗手指南。

Washing with soap and water is one of the key public health practices that can significantly slow the rate of a pandemic and limit the number of infections, preventing a disastrous overburdening of hospitals and clinics. But the technique works only if everyone washes their hands frequently and thoroughly: Work up a good lather, scrub your palms and the back of your hands, interlace your fingers, rub your fingertips against your palms, and twist a soapy fist around your thumbs.

用肥皂和水清洗是重要的公共衛生習慣之一，可以顯著降低大流行的速度並限制感染的數量，從而避免給醫院和診所造成災難性的負擔。但是技術上的需要每個人徹底落實：確實的搓洗肥皂產生細緻的泡沫，搓揉手掌和手背，交叉搓揉每根手指，用指尖摩擦手掌以及用手握住另一隻大拇指搓揉。

Or as the Canadian health officer Bonnie Henry said recently, “Wash your hands like you’ve been chopping jalapeños and you need to change your contacts.” Even people who are relatively young and healthy should regularly wash their hands, especially during a pandemic, because they can spread the disease to those who are more vulnerable.

或正如加拿大衛生官員邦妮·亨利（B??onnie Henry）最近說的那樣：“洗手就像切墨西哥胡椒一樣，你需要改變你的接觸面。” 即使是相對年輕和健康的人，也應該定期洗手，尤其是在大流行期間，因為它們可以將疾病傳播給更脆弱的人。

Soap is more than a personal protectant; when used properly, it becomes part of a communal safety net. At the molecular level, soap works by breaking things apart, but at the level of society, it helps hold everything together. Remember this the next time you have the impulse to bypass the sink: Other people’s lives are in your hands.

肥皂不僅能保護自己，如果正確落實洗手這件事，它將成為公共衛生安全網的一部分。在分子的層面上，肥皂能分解分子，但在社會層面上，它卻有助於將一切結合在一起。下次你有衝動衝到水槽時，請記住：他人生命掌握在你的手中。