首页
登录
职称英语
An American survey has shown that each year every employed person loses thre
An American survey has shown that each year every employed person loses thre
游客
2023-12-10
49
管理
问题
An American survey has shown that each year every employed person loses three to four working days from colds and allied complaints, and every school child loses five to six days of schooling. Colds waste more time than strikes. The conquest of the common cold is therefore a thoroughly worthwhile ambition.
In 1961, Sir Christopher Andrewes found that the great killing infections like syphilis or poliomyelitis are each caused by one specific micro-organism, or, at worst, a small group of closely related parasites. By contrast it has slowly become apparent that the common cold is not a disease but a large group of similar diseases, caused possibly, by anything between fifty and one hundred different organisms.
Much of Sir Christopher’s book is taken up by an account of the struggle to identify, the germs which do cause colds. At first it was thought that bacteria were responsible because certain bacteria are commonly found in the noses and throats of cold victims. But Dr. W. Kruse of the Hygienic Institute of the University of Leipzig in 1914 provided the first evidence that a virus might be concerned by launching experimental infections.
Since that time thousands of volunteers have subjected themselves to similar experimental infections, and for early twenty years most of such work has been done at Salisbury where the guinea pigs are rewarded by a ten-day holiday, all found that this "clumsy, expensive and unreliable" use of human volunteers was necessary because for a long time chimpanzees were the only other animals known to be susceptible to infection by common cold germs, and chimpanzees were far too expensive and unruly for routine use.
Growing cold viruses in the laboratory also proved difficult until one of the men involved demonstrated his possession of that most precious scientific faculty-serendipity.
Cold viruses were being grown with only moderate success in laboratory cultures of lung tissue from human embryos. The lung tissue cultures were kept alive by a salt solution containing added vitamins and a number of other ingredients. One day at Salisbury Dr. David Tyrrell found that this salt solution was faulty, and in order to keep his tissue cultures going he hastily borrowed a supply from another laboratory. When the imported solution was added to tissue cultures infected with cold viruses the lung tissue cells began to degenerate in a manner typical of tissues parasitized by active viral particles.
Dr. Tyrrell soon discovered that the borrowed fluid provided a more acid medium in his culture tubes than that produced by the native Salisbury brew. The nose provides a slightly acid environment, and Dr. Tyrrell realized that a degree of acidity was just what nose-inhabiting viruses needed in order to thrive outside the body. Thus a happy accident enabled a perspicacious scientist to modify the cold virus culture technique and thenceforward the whole exercise proved far easier and more profitable.
Much of common cold folklore is demolished. Draughts, chilling and wet feet do not bring colds on, says Sir Christopher, and clean, healthy living with lots of fresh air, plenty of exercise, good, plain food and a cold bath every morning may be good for the soul and the waistline, but does nothing to keep cold viruses at bay.
Colds are not very infectious — which will surprise most of us — so there is really no excuse for staying away from work when you have one. All the remedies so far invented have one thing in common — they are useless. In temperate countries, colds are commoner during the winter, but what the "winter factor" is which brings them on remains unknown. Most of us harbour cold viruses in our noses throughout the year, and many colds are probably not "caught" at all, but start because somehow the resident viruses become activated from time to time.
To write a book about colds at this stage, says Sir Christopher, is rather like writing a review of a play in the middle of the first act. Since he wrote those words, workers at Salisbury have announced the production of the first cold vaccine which will protect against infection by one particular cold virus. Unfortunately there are very many cold viruses and complete immunity from colds by vaccination would require the administration of a separate vaccine for every virus in the book. [br] One can deduce from the passage that colds are
选项
A、not given enough attention by doctors.
B、more frequent in America than in England.
C、due to bacteria.
D、likely to attack only very few types of animals.
答案
D
解析
细节推断题。定位到第4段。该段末提到人类作为研究感冒的试验者是必需的,因为黑猩猩是受与人类相同感冒菌感染的绝无仅有的动物之一,故可推断只有极少数动物患感冒,因此D为正确答案。A项与文章首段指出的“对抗感冒极具意义”不符;B项在文中并未提及,也无事实根据;文中的研究表明感冒是由virus(病毒),而非bacteria(细菌)引起的,故排除C项。
转载请注明原文地址:https://tihaiku.com/zcyy/3261681.html
相关试题推荐
Ananonymouspersoninachatterchambersaid,"Ibelieveinserendipity,ka
______isregardedbyAmericanas"thefatherofthecountry".A、JeffersonB、Frank
The"firstAmericans"were______.A、theBlackSlavesB、thePilgrimsC、theIndians
ThefirstimmigrantsinAmericanhistorycamefrom______.A、EnglandandGermanyB
OneofthesignsoftheawakeningoftheAmericanIndiansis______.A、thereappea
People’sattitudetowarddrugsvariesfrompersontoperson.Someregarditas(
People’sattitudetowarddrugsvariesfrompersontoperson.Someregarditas(
People’sattitudetowarddrugsvariesfrompersontoperson.Someregarditas(
People’sattitudetowarddrugsvariesfrompersontoperson.Someregarditas(
People’sattitudetowarddrugsvariesfrompersontoperson.Someregarditas(
随机试题
BythetimeIfinishedhighschool,myinterestinanimalshadgrown,anden
Noonecandenythatpesticidehaveimprovedtheabilityoffarmerstobrin
某企业本月生产甲、乙两种产品,有关资料如下: (1)甲、乙产品产量、销售单价及
A.|A|^2 B.|A|^n C.|A|^2n D.|A|^2n-1
中央银行确定货币供给统计口径的标准是金融资产的()。A.稳定性 B.收益性
脉络膜血管主要来自什么动脉A.睫状后长动脉 B.前睫状血管系统 C.睫状后短
小红调查完公园的生物种类后,将有关的生物分成了动物、植物和其他生物三类。他所采用
如图,两个同心圆构成的圆环被均匀地分割成7份,连同中间的小圆共8个区域。若要给这
十四椎下旁开3寸的穴位是( ) A.大肠俞 B.胃俞 C.肾俞 D.志
人在每一瞬间,将心理活动选择了某些对象而忽略了另一些对象。这一特点指的是注意的(
最新回复
(
0
)