The Story . . .
While processing the records of the Military Order of the Loyal Legion of the United States, New York Commandery, we came across a poignant relic of the Civil War: a note passed between the lines at the Battle of Antietam, one of the bloodiest battles in the history of the nation.
The note was sent to the Loyal Legion by Union Captain William J. Carlton, who explains in an accompanying letter that while he was posted “in front of the little Dunker church” – the site of some of the sharpest fighting of the battle – a Confederate soldier approached with a flag of truce and handed over a note asking for the body of confederate Lieutenant Paul Newton. The note, signed by Colonel A.H. Colquitt – a Georgian who after the war was elected to the U.S. Senate — describes Newton as “tall and well proportioned, has … blond hair and mustaches, with 2 stars on the collar of his coat.”
Carlton took the note to Union Generals William B. Franklin and Henry Warner Slocum, who agreed to comply with the request, and the body was sent across the lines.
The story doesn’t end there, though. In a sad postscript, Carlton notes that the following morning, after the Confederates retreated into Virginia, he saw the body of Paul Newton with a number of other dead Confederate officers left abandoned on the field: “evidently they had not the means of transportation and had to leave their fallen comrades to be found in unknown graves.”
There is a final, compelling detail that makes this note a peculiarly vivid link to the past: it bears a sizeable stain of what appears to be blood. Considering the circumstances, this would make perfect sense, but could we confirm that the stain is in fact civil-war era blood? We asked our wonderful conservation department to investigate.
The Science . . .
The conservation department has limited testing equipment, so conservators researched different methods of non-destructive analysis they could pursue. They eventually connected with Dr. Dan Gareau, Biomedical Engineer at Rockefeller University. Dr. Gareau recommended using Fiber Optic Reflectance Spectroscopy (FORS) to analyze the stain because of its non-destructive (no-contact) method and use of low power light.
A unique absorption profile can be made using FORS by measuring the amount of light a sample absorbs at different wavelengths. Dr. Gareau has experience in analyzing hemoglobin states of blood inside the body and can identify hemoglobin’s spectral fingerprint when analyzing blood spectroscopically. He was unsure how well hemoglobin’s fingerprint would hold up over time and was curious to find out what profile a (possibly) 150-year old blood stain on paper would produce.
Although Dr. Gareau was confident of his ability to obtain the stain’s profile, analytical data of known old blood contemporary to the stain was needed as comparison in order to positively identify the stain as blood.
Conservators searched for blood studies of Abraham Lincoln’s artifacts at Ford’s Theatre and Mary Todd Lincoln’s bloodstained cloak at the Chicago Historical Society. Unable to find useful data, the conservators decided to create their own known samples, and collected stains from blood (donated by one of the conservators) with other possible staining substances such as tea, coffee, and rust.
Spectroscopic evaluation . . .
The stained note and homemade known samples were brought to Dr. Gareau, which he analyzed using his spectroscope, an assemblage of a spectrometer, light source, and fiber-optic probe. *
Dr. Gareau chose three spots within the stain to analyze and took three measurements of each spot. The measurements were taken by positioning the note so that the selected spot was under the fiber probe. For each spot measurement, he also took a measurement of a blank area of the note near the stain to use as a blank measurement. He then calculated the absorption of just the stain by using this equation:
The resulting data is a light absorption profile of the stain plotted as a function of wavelength of light. Figure 1 presents all the profiles taken of the spots, the known blood sample, as well as coffee, tea, and rust. In the figure, the wavelengths start at 300nm, which is ultraviolet light and end at 900nm, which is infrared.
* Components of spectroscope used in this study
- Spectrometer – HR2000, Ocean Optics, Dunedin, FL
- light source – HL2000, Ocean Optics
- fiber-optic probe – QR600-7-UV125BX, Ocean Optics.
Absorption spectrum for stain on the note and modern blood, rust, coffee and tea stains
According to Dr. Gareau, the profiles or spectra of the note stain did have something that resembled hemoglobin’s spectral fingerprint, even without the fine details coming through.
To better compare the stain’s spectra with those from the known samples, Dr. Gareau normalized them so that they all had the same value at 600nm, which is within red light. In biomedical instrumental analysis, oxygenated hemoglobin in blood is characterized by activity in green or in red light. In Figure 1, the spectra of the unknown stain and of the known blood sample have remarkably similar slopes at 600nm. The data suggests that the unknown stain contains hemoglobin and could be blood. The spectra of the tea, coffee, and rust samples all have disparate slopes, disqualifying them as possible sources.
A wider view of the spectra, in Figure 2, reinforces the resemblance in absorption profiles between the stain and the known blood samples.
What does all this mean?
To determine with 100% accuracy, the source of the stain would require more destructive testing that would damage or even destroy the artifact. But our scientific investigations were sufficient to confirm that the rusty blotch across the note is, in all likelihood, blood – not tea, or coffee, or rust, but the blood of a human being who was alive during the civil war. It’s hard to define, but somehow this knowledge transforms a merely interesting primary document into a genuine civil war relic. However ironic it may be, the blood of a dying soldier has, over 150 years later, brought a historic document to life.
N-YHS sincerely thanks the following people for their interest and assistance:
Rockefeller University Hospital
- Barry Coller, M.D., Physician in Chief, Vice President for Medical Affairs, David Rockefeller Professor, Laboratory of Blood and Vascular Biology
- Mike Dietz, Mechanical Engineer
- Dan Gareau, Ph.D. Biomedical Engineering, Laboratory of Investigative Dermatology
- James G. Krueger, Director, Milstein Medical Research Program, Senior Attending Physician, D. Martin Carter Professor in Clinical Investigation, Laboratory of Investigative Dermatology
- Sarah J. Schlesinger, M.D., Associate Professor of Clinical Investigation, Senior Attending Physician, Laboratory of Cellular Physiology and Immunology
Other valuable resources
- Robert Gaensslen, Ph.D., Professor & Director of Forensic Science, University of Illinois at Chicago
- Laura Anderson, Museum Curator, National Park Service, Washington DC
- Chicago Historical Society and the University of Illinois at Chicago conference to consider authentication of Mary Todd Lincoln’s cloak. June, 1999.
N-YHS Fiber Conservation Department
- Alan Balicki
- Heidi Nakashima
- Janet Lee
- Sue Kriete