"They were working under a Heckscher Foundation grant studying just how antiseptic solutions destroy bacteria. It has always been held that some chemical change went on, but this theory they disproved. It is a process of absorption. If enough of the chemical adheres to the living bacterium, the living protoplasm thickens and irreversibly coagulates. It resembles a boiling without heat. I have seen some of their slides and the appearance is exactly what I see in this tissue." Captain Murdock bent over the microscope with a new respect for Dr. Bird in his face. "I agree with you, Doctor," he said. "This tissue certainly looks as though it had been boiled. It is certainly coagulated, as I can plainly see now that you point it out to me. You believe, then, that it is a simple case of gassing?" "If so, it was done by no known gas. I have studied at Edgewood Arsenal, and I am familiar with all of the work done by the Chemical Warfare Service in gases. No known gas will produce exactly this appearance. It is something new. Carnes, have those horses been brought up yet?" "I'll see, Doctor." "If they are, bring one here." * * * * * In a few moments the body of a dead horse was dragged into the operating room and Dr. Bird attacked it with a rib saw. He soon laid the lungs open and dragged them from the body. He cut down the middle of one of the organs and shaved off a thin slice which he placed under the lens of a powerful binocular microscope. "Hello, what the dickens is this?" he exclaimed. With a scalpel and a delicate pair of tweezers he carefully separated from the lung tissue a tiny speck of crystalline substance which glittered under the red light in the operating room. He carefully transferred it to a glass slide and put it under a microscope with a higher magnification. "Rhombohedral regular," he mused as he examined it. "Colorless, friable, and cleaving in irregular planes. What in thunder can it be? Have you ever seen anything like this in a lung, Murdock?" The medical officer bent over the microscope for a long time before he shook his head with a puzzled air. "I never have," he admitted. "Then that's probably what we're looking for. Start slicing every lung in this place and look for those crystals. Save them and put them in this watch glass. If we can get enough of them, we may be able to learn something. Carnes, get the rest of those horses in here and open them up." Two hours of careful work netted them a tiny pile of the peculiar crystals. Some had come from the lungs of the dead animals and some few from the lungs of the dead soldiers. Dr. Bird placed the crystals in a glass bottle which he covered with layer after layer of black paper. "Get me more of those crystals if you can find them, Captain Murdock," he said, "and in any case, leave the bodies here for further study. Davis and I will go to the laboratory and try to find out what they are. Carnes, hasn't Miss Andrews showed up yet?"