When America starts to run out of scientists in the next 10 or 15 years, don't blame Robert Bottoms. He's sounding the alarm as hard as he can.

Rinnnggg! The Soviet Union is far outstripping us in science education, and Japan, with half our population, is producing twice as many scientists as we are.

Rinnnggg! The number of undergraduate science majors has fallen by half since 1960, and in another 10 years, the batch of home-grown scientists will have dwindled to crisis proportions.

Rinnnggg! Half the 1,100 doctorates awarded in physics last year were awarded to foreign nationals, and in another two years, the same thing will be true in chemistry.

How did we wind up in such a mess? Bottoms, president of DePauw University, says it sneaked up on us from a number of directions. The recent emphasis on "vocationalism," the "glamorization of the MBA" and the explosive growth in "soft knowledge" fields -- public relations, marketing and so on -- have captured young people who might have gone into science. High school science education has slipped, the brighter students having learned from their advisers that they can make a lot of money doing something else. De-emphasis of science instruction has reduced the number of science teachers.

During the past 15 years, after a spurt of post-Sputnik interest, "we have forgotten about science," he says. "Because the graduate schools were full, we thought we were doing okay. But they were full of foreign nationals, most of them planning to return to their native lands. . . . Within 10 years, there will virtually be no large home-grown batch of scientists available."

The solution figures to be as complex as the trends that produced the problem, but Bottoms thinks he knows one thing that can help: more help for colleges like DePauw.

Bottoms' intense interest in science education goes back two years, when he and 47 other presidents of highly competitive liberal-arts colleges met at Oberlin College. "We did some studies and discovered that many PhDs from the big research universities did their undergraduate work at small liberal-arts schools like ours. For instance, one Midwestern state university had more PhD candidates in chemistry than it had undergraduate majors in chemistry.

"That is significant for two reasons. First, both industry and the National Science Foundation have tended to focus on the research institutions, neglecting the contribution of the liberal-arts schools. Second, while the large universities, with 200 or 300 students in a single class taught by a graduate student, can do an adequate job of teaching science to committed students, it's hard for such schools to get young people interested in science in the first place. You can learn science that way, but if you have a class of 25 taught by a full professor, you have a better chance of getting an uncommitted student excited about science."

It is the failure to excite students about science that helps to account for the crisis, Bottoms believes. "We looked at the journals that publish scientific articles, and we found that a third of the articles authored by professors from liberal-arts colleges listed undergraduate students as coauthors. Less than 1 percent of the articles authored by professors at the major research universities were coauthored by undergraduates."

The opportunity to work with the top science faculty, he said, accounts for another interesting statistic: between 1975 and 1984, the proportion of freshmen interested in a science major fell from 13 percent to only 8 percent, while at the top liberal-arts colleges, the proportion has remained at about 28 percent.

Bottoms obviously would like more outside investment in science education and research at schools like the Oberlin 48. But much of the problem has been created by educators and must be attacked by educators, he believes.

"Advisers can tell students that the pursuit of science is a noble one, as generations since the Renaissance have believed. Colleges can stress through their admissions literature the beauties of the scientific method and experimentation -- the beauty of the discipline required to understand a complex equation or a lengthy experimental process. We can tell students that majoring in science is not just a convenient way to enter medical school but an end in itself: a discipline as well worth pursuing as psychology and communications and economics.

"If these attitudes are changed, we will not have to wake up in another 30 years to find that our scientists have disappeared completely."