A plane flies over a city, and drops a could of plague on the target, wiping it out. It is not the instantaneous mass murder of the mushroom cloud -- it is the slow mass murder of a contagious, incurable disease.

This is chemical-biological warfare, the newest thing in military destruction. The United States is already using it against crops in Vietnam, and is conducting research in the possibility of using it against people.

But a group of American scientists--led by two Harvard professors--is trying to convince President Johnson to abandon the project. Matthew S. Meselson, professor of Biology, and Dr. John T. Edsall, professor of Biological Chemistry, have collected the signatures of over 5000 scientists in support of a letter to Johnson asking him to stop using these weapons in Vietnam, and to "categorically declare the intention of the U.S. to refrain from initiating the use" of them in the future.

At least two Nobel Prize winners are among the signers of the letter, which will probably be sent to the White House in January. All of the signatories have Ph.D.'s or M.D.'s, and over 100 are members of the National Academy of Sciences. It is perhaps the most impressive collective expression of scientists' feelings since physicists lobbied in 1946 to keep control of atomic energy out of the hands of the military.

Super-Insecticide

Chemical and biological weapons don't have to be as dangerous as nuclear armaments, but they can be. A chemical weapon works like an insecticide, except that chemicals may range from only temporarily debilitating to lethal. Biological weaponry works like any disease. In addition to ranging from non-lethal to lethal, a biological weapon can also be non-contagious or contagious. A contagious weapon could even kill people who were not in the original target zone, since the germs could spread to other areas.

After listening to Meselson inveigh against biological warfare, one wonders how anyone anywhere could be in favor of it. Meselson says it is militarily inconvenient, socially disastrous, and no more humane than any other form of war.

For the military, chemical-biological warfare (CB warfare, for short) is too unpredictable. Military strategists cannot measure the exact range a virus will cover, the way they can for a fusion blast. Resistance to the disease would be unknown, and would vary with the victims. The problems of delivering the dose, which would have to be in the form of an aerosol cloud, are technically difficult, Meselson suggests. "Even if it could be improved in the remote future," he says, military control "would suffer along the way."

Meselson admits that CB weaponry is less unpredictable as a strategic weapon. But if we are interested in larger areas, we already have the Bomb.

Although CB weapons work very well against crops, it is easy for human beings to protect themselves by wearing gas masks or entering shelters -- provided they are warned. Only in a surprise attack, then, are the weapons effective. "It puts an enormous premium on the low blow," Meselson says.

The unpredictable, uncontrollable nature of this new style of war has more than just military import. "One step toward controlling war in society," Meselson suggests optimistically, "is to move towards weapons we can control."

Nuclear weapons are reasonably controllable. At least, it would take some time and bureaucratic shuffling about before a great nation could decide to drop one. And nuclear weapons will always be under the thumb of massive, relatively rational, political units because it is too expensive for an individual to make one in his workshop.

There are no such guarantees for CB arms, Meselson maintains. Although they are not cheap now, they will be once the pioneering stage is completed. The result, he suggests, could be disastrous. "Today, a madman in America might climb to the top of a tower for a shooting spree, or put a bomb in an airplane. But if CB weaponry were conventional, maniacs would constitute an enormous threat. An insane man could wipe out New York City."

It would seem possible, of course, for the United States to develop a formula for inexpensive CB weapons without letting the secret out to the public. But once it is known that such a formula exists, people are more likely to have the initiative to duplicate it. Meselson does not carry his argument this far -- he simply implies that if we must have mass annihilators, expensive ones are less undesirable than cheap ones.

More Humane?

Against this indictment, the proponents of CB warfare offer basically one argument: that this new weaponry would create a more humane way of making war. Although CB weapons can be lethal, the emphasis is certainly on the non-lethal versions, because it is their ability to incapacitate without killing that makes them unique. If it is noble to kill only soldiers in war while sparing civilians, how much more noble it is to render the soldiers unable to conduct war, without killing anyone.

Meselson believes that this argument breaks down when carefully examined. First, he says, one must realize that lethal and non-lethal are poles on a continuous spectrum of the effects of weapons. A weapon which is non-lethal can either temporarily incapacitate (like tear gas) or permanently maim. As long as it does not kill, it is non-lethal.

The use of non-lethal CB weapons would serve as an "opening wedge," Meselson fears, to a gradual movement along the spectrum in the direction of kill. This is not just a legal point -- although there are problems of which types of weapons are outlawed by which treaties -- but a practical one as well. The techniques of manufacture, the methods of distribution, and the logistics of employing the devices would be about the same for lethal and non-lethal CB weapons. Meselson says.

It is like teaching a boy all there is to know about shooting rubber-tipped arrows from his bow, and expecting him never to try a steel-tipped shaft. Meselson would say that the rubber-tipped arrows are nice, but the steel-tipped ones are more horrible than anything now known. Can you expect a boy to refrain from experimenting, just once?

"There are individuals in every military," Meselson says, "who want to run the whole gamut of weapons." Having non-lethal weapons would not make war less lethal, he asserts. "It is a ridiculous assumption that giving field commanders weapons that don't need to kill means the commanders will not kill. What will happen is that non-lethal weapons will be used in conjunction with killers."

This distinction between the lethal and the non-lethal also leads to some touchy problems in international relations. If a country has a policy of using only non-lethal CB arms, Meselson says, only that country knows for sure it is a non-lethal policy. And there is, at this time, no biological equivalent for seismographic detection of nuclear testing, so suspicious nations could not find out what is actually being done in the enemy camp.

U.S. Responsibility

If CB warfare becomes conventional, Meselson believes it will be due primarily to the United States. Conversely, control of this style of war must also be America's responsibility. It is the U.S. which is now using chemical weapons in Vietnam, and it is the U.S. which refused to ratify the 1925 Geneva Protocol which deplores the use or even development of such weapons. The Protocol was written by the U.S., signed by the U.S., but not ratified by the Senate. America has nonetheless always had a "cautious respect" for the treaty, according to Meselson.

If it is America's responsibility to show the world the way to abolish CB warfare, Meselson's activity reflects the idea that it is the scientists' responsibility to convince America to do it. Scientists do not usually lead political movements for a variety of reasons, including the fact they do not want government to restrict their freedom in science, so they reciprocate in advance. But on certain issues, these men who create in laboratories feel that they understand their offspring better than the government which charges itself with the responsibility of bringing up the child. It happened to physicists after World War II with atomic energy. And it is happening now to biologists.

There is one fundamental difference between the two campaigns. The development of atomic energy was a well-kept secret during the war -- Harry Truman had never heard of the Manhattan Project until he assumed the presidency, which was but a few months before the U.S. struck against Japan. Scientists who were used to the free channels of communication which have characterized the profession for centuries forced themselves to develop the weapon for their country in an emergency, with little discussion of the virtues of the plan. CB warfare, on the other hand, is being developed largely in the open.

Scientists' Fears

Only after the war could physicists express their fear of what they had created. But in journals of recent years, much has been written about CB weapons. The U.S. is not making any attempt to hide the fact that it is doing research.

So Meselson and Edsall are not leading a protest of scientists who worked on the weapon and now want it responsibly suppressed. They are men who feel they understand what the weapon would be like, and they want to stop this Manhattan Project before it progresses too far.

It is not easy to marshal scientific opinion in this country. "I do not think," Meselson admits, "that the majority of scientists wish to take political action on this or any other issue. A substantial minority does."

"I am amazed," he continues, "with the response to our letter to President Johnson." Only about 3000 copies were mailed out, primarily to members of the Federation of American Scientists (which, incidentally, was organized after World War II to fight military control of atomic energy) and yet over 5000 have signed.

Presdent Johnson has already received a copy of the letter with 22 signatures affixed. It was sent to the White House in late August, "as a courtesy measure." No one knows how he will react to a message with 5000 learned signatures.

For Meselson, of course, the prime issue is to keep closed "this Pandora's box." But his efforts will also be a significant test of whether a large number of scientists can, in their own sphere, influence the Chief Executive, in much the same way they influenced Congress two decades ago