When the Museum of Comparative Zoology opened more than 100 years ago with a small specimen collection kept in limited space and financed on a shoestring budget, few people could have predicted that it would become one of America's best natural history collections and one of the preeminent teaching and learning grounds for natural historians.

The museum keeps a low profile. It has its public side, with displays next to the glass flowers exhibit at the University Museum. The public museum contains a vast array of exhibits--from stuffed birds, mammals, and dinosaurs to exotic fishes, fossils and other creatures found by natural scientists. Although many children and adults wander about throughout the day, patrons only see a small part of the actual collection.

The displays the public visits are a small part of the entire complex of turn-of-the-century buildings behind the Science Center, on Oxford St. Almost half of one building is devoted to the scientific research collections that form the core and purpose of the museum. The side entrance is marked "Closed to the Public." Within those doors, students and professors have their offices amidst rows of cabinets which house large collections of animals that are seldom seen by visitors.

Within the giant cabinets that fill each floor of the building, scientists store collections of an incredible array of creatures, from the largest bird in the world to the smallest owl, fossils of the earliest known life or fossilized mammoths. In all, the museum houses collections of almost every historical precursor to men, including a marine biology section.

Most of the rooms in the museum smell of moth balls, alcohol and dust. By simply unlocking a cabinet, and pulling out one of the drawers, students can confront face to face a giant harpy eagle which eats 30 pound mammals.

Although he is stuffed here, the creature would otherwise be seen only in South America.

So the collection serves primarily not as a showcase for oddities and rarities but as a teaching ground for studying and observing animals before or after an expedition. Graduate students and professors in the museum have stories to tell about where they've gone to study and observe their particular fish, reptile, or animal. Some of them keep live specimens in their small offices, so walking into an office may mean being confronted with a room full of glass tanks of snakes or frogs.

"We are probably the best example anywhere in the country of this great integration between the museum function and the academic, teaching function," says James J. McCarthy, director of the museum. "Unlike any other Harvard museum, the activities are very intimately interwoven with the teaching functions of the department," he adds.

It's not surprising that many of the curators see the collections as akin to libraries; things are collected that might never be used but are simply preserved for certain classical traits. Like many libraries, the Museum has a rare books collection.

"Any scientific collection is essentially a library," says Ruth C. Turner, co-curator of the mollusk department. "The collection can give you enormous amounts of data."

"So these collections have become increasingly more important as animals become extinct or as environments change. We have things from Miami where now you see skyscrapers. As man alters the enviroment, the collections become more and more important."

"The collection is like Houghton [Library]," says Raymond Paynter Jr., curator of the bird collection. "It's full of treasures but its growth is very slow."

The bird collection ranks third in the country with about 350,000 specimens, Paynter says. Among these is a collection of Chinese birds that "are the best in the world, better than even China," he says.

Along with the Chinese birds are two great auks, an extinct relative of the penguin. "No other museum has more than one," Paynrwe says.

Where the bird collection is numbered by specimen, though, the invertebrate paleontology collection is quantified in tonnage or groups of fossils. This fall the department had to throw away almost 20 tons of fossils because they were taking up too much room and no one could catalogue them. Only four fossil collections surpass Harvard's.

"We have a little bit of everything," says assistant curator Felicita C. D'Escrivian. "We have a very good cephalopod collection and the trilobites are very, very good," she adds.

The museum houses vast collections. The mammals department has 85 percent of all mammal genera, according to Maria E. Rutzmoser, acting director of the mammal collection. "You have certain masterpieces of art as part of a national treasure and this is a planetary treasure," she says.

A curator, who maintains and expands the collection in addition to full-time duties as a professor, heads each collection.

The curators do occassional research with their collections. For example, Turner says, Agassiz Professor of Geology Stephen J. Gould, curator of Invertebrate Paleontology (see accompanying story), works with his-collections and the mollusks department for his evolutionary studies.

Expanding the collections and doing research with them are, therefore, closely connected. "The two are so closely integrated in that you need to be able to go where you want for your research and you need the collection," says Turner.

As a result of her own special study, the mollusk department "has the best collection of ship worms anywhere in the world with 50 to 75 times the amount," she adds.

For the most part, collecting for the museums is selective Professors and graduate students bring back specimens from their work and the curator chooses from these samples. But the museum no longer engages in the large-scale collecting for the sake of collecting expeditions that it once did.

The mammals department has the largest collection of gibbons because of expeditions in Borneo and Thailand that "decimated whole hill sides," Rutzmoser says, adding. "We wouldn't do that anymore."

At times, the Museum's collections and expertise have been called to strange tasks. During World War II, when U.S. troops were in the Pacific, an indigenous snail became a major health problem spreading schistosomiasis. Because of the collections, the museum was able to give the Army distribution patterns for the snails and tell the soldiers where dangerous areas existed Eventually a graduate student from the museum joined the soldiers in scouting streams ahead of time, collecting the snails and warning the troops where to avoid the snail. Turner says.

Most of the museum's collecting is not done in such an odd way, though it certainly has a long history of strange collecting expeditions. Today as in the past, the museum's attempts to expand are hampered by space and money limitations.

The museum began with a small collection of Professor Louis Agassiz's in the mid 19th century. Agassiz's collection was the result of years of personal work and care but he later sold it to Harvard, forming the core of the collection. And while most of today's curators say that they don't have enough room, the early collection had neither enough space nor a permanent location.

In its first few years, it occupied the site of Hemenway Gym. The original building then became a club for the museum assistants while the collection migrated to the site of the Peabody Museum. In 1852, the University bought the collection and put it on more stable footing. Massachusetts incorporated the trustees of the museum in 1859 and gave it a relatively large trust fund to expand, but the scientific research was left to the University and Agassiz. One year later Agassiz persuaded the University to donate the land where the museum now stands.

By the end of 1860, the first part of the building was standing, and Agassiz and his 19 assistants began collecting and expanding. From then until 1901, the museum added eight new buildings all integrated into the main structure. During that time, it launched several collecting expeditions and became best known for its Brazilian fish.

A year ago, the museum was ranked the top university collection and training ground in its field by the National Academic of the Sciences not just for fish anymore.

Other museums in the nation are bigger and richer the two most notable being the Smithsonian and New York's Museum of Natural History in New York. The Smithsonian, for example, is expanding at a rate of almost one million specimens a year and receives substantial funding subsidies fron the federal government. But for a University museum. Harvard has one of the most diverse and largest collections.

The museum is limited by space, and most department curators say that while they are expanding, progress is very slow. Many of the departments are currently engaged in reorganizing their collections and bringing them out of disrepair. Funding for such activities comes primarily from the federal government and National Science Foundation grants, McCarthy says.

The museum has its own endowment which helps pay for building upkeep and overhead and also receives some aid from the faculty, which pays the professors salaries and for the library, he adds.

Not the richest museum around, the MCZ has gone through periods of tight finances. "You don't make money at this," Turner says. "People do this because they love it," she adds.

The discovery of asbestos in the museum more than a year ago made museum workers stop and think about their work, but since that finding, the museum has taken steps to protect workers from the cancer-causing material. "To the best of our knowledge, there is no asbestos hazard in the Museum," McCarthy says, adding, "I am confident that the job was done properly."

"I don't think it scared anybody," says Ronald C. Eng, a curatorial associate in Invertabrate paleontology. "When the found out about it they took steps," he remarks, saying, "People weren't frightened; they still come in every day and work in the building."