2018考博英语阅读经济学人文章每日精析：对抗衰老
考博英语阅读大部分博士研究生招生院校都使用《经济学人》杂志文章作为题源，新东方在线考博频道为考博生们将其中的文章进行深度分析，希望能提高大家的考博英语阅读水平，读懂长难句。
Fighting ageing
对抗衰老
Youthful spirits
青春血液
Blood transfusions from young animals can revitalise old ones. Trials are now running to see if that is true for people, too
输入年轻动物的血液可助年老动物重现活力。在人类身上是否亦是如此?试验正在进行中
IT WAS one of the oddest experiments in the history of dentistry. In the early 1950s a researcher called Benjamin Kamrin was looking into the causes of tooth decay. To do so, he turned to that scientific stalwart, the lab rat. Specifically, he cut small patches of skin from pairs of rats and then sutured the animals together at the site of the wound. After about a week of being joined in this way, the animals’ blood vessels began to merge. The result was two rats whose hearts pumped blood around a shared circulatory system. This state of affairs is called parabiosis.
这是牙科史上最怪异的试验之一。20世纪50年代初，一位名叫本杰明·卡姆林(Benjamin Kamrin)的研究人员为研究蛀牙的成因，求助于科学试验的忠实伙伴——大鼠。具体来说，就是从好几对大鼠身上分别切下小块的皮肤组织，然后在切口处把这些大鼠两两缝合在一起。如此合体约一周后，它们的血管开始融合。结果是两只大鼠的心脏会向共享的循环系统供血。这种情况被称为联体共生(parabiosis)。
Parabiosis works best on animals that are closely related genetically. By getting his rats to share blood, as well as genes, and then feeding the animals a variety of diets, Kamrin hoped to prove (which he did) that it was sugar in food, and not some inherent deficiency in individuals, that was responsible for rotting their teeth.
在基因密切相关的动物身上，联体共生的效果最佳。卡姆林让这些大鼠共享血液和基因，然后向它们投喂各种食物，希望以此证明导致龋齿的是食物中的糖分，而非个体的某种先天不足。他最终成功证明了这一点。
Other people, though, have used the technique to find more striking results. For example, mammalian bone density usually drops with age. Three years after Kamrin’s work, however, a gerontologist called Clive McCay showed that linking an old rat to a young one boosted the density of the oldster’s bones. In 1972 another paper reported, even more spectacularly, that elderly rats which shared blood with young ones lived four to five months longer than similarly old rats which did not.
其他人则利用该技术获得了更惊人的发现。例如，哺乳类动物的骨密度通常随年龄增长而下降。然而，卡姆林的研究过了三年后，老年病学家克莱夫·麦凯(Clive McCay)证明了把老年大鼠和幼年大鼠联体能提升老年大鼠的骨密度。1972年，另一篇论文更令人咋舌地指出，相比同类老年大鼠，分享了幼年大鼠血液的老年大鼠能多生存四至五个月。
The rats themselves, unsurprisingly, were not always keen on the procedure. Early papers describe the dangers of “parabiotic disease”, in which one animal’s immune system rebels against the foreign blood, and also explain how rats must be socialised carefully before being joined, to stop them biting each other to death.
当然，大鼠们本身并不太喜欢这个过程。早期就有论文描述过“共生病”的危害——发病时动物的免疫系统排斥外来血液。论文也解释了在把这些试验鼠联体之前，必须先小心地让它们熟络起来，防止互相撕咬致死。