Matthew S. Meselson, Professor of Biology, said last night that present U.S. policy towards biological and chemical warfare is one which can only stimulate other countries to develop their own chemical and biological weapons.

"Once you start using gas to kill, you start an enterprise whose end is impossible to calculate," he said in his argument for a basic change in the use and development of chemical and biological weapons.

Meselson's argument was that small-scale use of B. and C. weapons (the lines between the two are blurred) quite conceivably could escalate into large-scale disastrous biological warfare.

Because of the nature of B. and C. warfare, he noted, the development of defensive weapons does not necessarily keep pace with the development of offensive ones. Since it would be possible to develop an almost unlimited number of different lethal organisms, for example, an organism by organism defense would be extremely difficult to develop. For this reason, mechanical defenses, such as detection systems for microorganisms and new types of gas masks, are the most practical.

'Propagate a Disdain'

Therefore, Meselson maintained, the United Staets, which spends about $200 million yearly on such weapons development, should do what it can to propagate a disdain" for biological and chemical warfare research.

The government should work towards some arms control agreement on biological and chemical warfare testing, he said, noting that sophisticated techniques now available might be able to detect a test thousands of miles away.

If the United States begins to change its own policies and work towards the limitation of weapons development, "people might get the idea that there is going to be a treaty in a couple of years so we better not put too much money into this type of research," he said.