- Historic Sites
Dr. Campbell’s Remarkable Experiment
June/july 1982 | Volume 33, Issue 4
In the last issue we told how the United States in World War II attempted to bring destruction to Japanese cities by peppering them with bombcarrying bats. Bizarre though that experiment sounds, it was not the first time the Americans tried to enlist the help of bats. Herewith, the strange tale of Dr. Campbell’s lifelong obsession.
The story of the bat towers, large wooden structures designed to garrison colonies of bat “soldiers” in the war on malaria, may sound like a tall Texas tale. But the towers were real. A few even remain standing today.
When Dr. Charles A. R. Campbell graduated from Tulane Medical School in 1899, he returned to his native San Antonio to specialize in the treatment of malaria, then a terrible problem throughout the South. Campbell had been greatly excited by recent proof that the mosquito was the disease’s vector. Now, with the enemy a wellidentified foe instead of a vague “miasma,” a new age of combating malaria had begun. As early as 1900 Dr. Campbell began to consider using bats.
Mosquito control was still an infant science at the turn of the century: crude metallic poisons were dumped into breeding sites, and corn oil, cactus paste, or petroleum products were spread over the surface of waters.
The idea of drafting bats was perhaps not as bizarre as it now seems. As early as the 1850’s English sparrows were introduced into the Northeast to fight insect populations in growing urban areas. The introduction of the Vedalia beetle into California in the 1880’s to combat the cottony-cushion scale menacing citrus groves had been an outstanding success. Even while Campbell was developing his scheme, there were researchers scouring distant parts of the world to find the natural predators of such banes to American agriculture as the gypsy moth, the brown-tail moth, and the sugar-cane leaf hopper.
Campbell knew of this work yet felt there was no need to send agents to remote lands when, “in the little bat, we have right at home a friend whose wonderful habits we can take advantage of in the saving of precious human lives.”
The burning question that occupied Dr. Campbell’s mind after 1900 was, Could bats, like bees, be colonized and made to multiply in strategic locations? In 1902 he began a series of experiments with boxes scented with bat guano, which he placed in trees, under country bridges, in large warehouses, in livery stables, and even on his front porch. The experiments were all failures: none of his boxes attracted bats.
Disappointment spurred Campbell to begin a study of the numerous caves in the area. Many of these bat caves had a long history of profitable trade in guano, which had been used during the Civil War to make saltpeter for gunpowder. Since the war it had been sold for fertilizer. Most of the caves contained over a million bats and produced over sixty tons of guano a year.
Impressed with the size of the bat colonies and with the fact that their guano production was so lucrative, Dr. Campbell brought a new element to his scheme. He began to dream of great towers, containing hundreds of thousands of bats each, which not only would control malarial mosquitoes but also would have a commercial element to encourage their construction. Bats for health and healthy profit; bats converting mosquitoes into dollars.
The world’s first bat tower went up in 1909. Dr. Campbell had by this time so neglected his medical practice that he needed to borrow money from a friend to pay for its construction. The cost was five hundred dollars; the site was a small corner of the U.S. Department of Agriculture experimental farm some six miles south of San Antonio.
To attract bats Campbell seeded the tower with guano and, inside, hung several smoked hams. Outside he stacked several cords of mesquite wood and erected a night lantern on a post—both measures to attract insects. Finally he placed several barrels of water nearby to serve as breeding tanks for mosquitoes. Weeks, then months, passed. The tanks produced so many mosquitoes that he was requested to remove them from the farm. No bats came to his tower.
As a last-ditch effort, Campbell spent two hundred and sixty dollars remodeling the interior of the tower in the spring of 1910. He had recently observed that at the deserted main exhibition building of the old fairgrounds just a mile away, there was a large colony of bats. Now, through the good offices of the mayor of San Antonio, Dr. Campbell had a fire department hose company placed at his disposal. Throughout one day, the firemen fought the bats with streams of water in an attempt to get them to relocate in Campbell’s tower. The panicked bats, however, merely circled clamorously from one part of the building to another.
The failure of this first tower seems to have affected Dr. Campbell deeply. In his memoirs he describes how he afterward “racked his brain, spending many sleepless nights, planning, pondering … even dreaming over this most vital of all problems, colonization.” Surely, he felt, there must be some way. “Was the solution to the problem that meant so much to humanity, to countless millions yet unborn, to go unsolved?”