aid. even if an army were able to overcome the shortage of ambulances, it was really the lack of organization that made it difficult to recover the wounded on the battlefield. in some cases, those who manned the ambulances were corrupt and sought to steal from the ambulance wagon and the wounded passengers while in some situations they even refused to gather hurt soldiers. with an insufficient number of ambulances performing assigned tasks, the wounded looked to their comrades to carry them to safety and in essence this removed many soldiers from the battlefield. owing to the overall lightness of the ambulance the ride was very uncomfortable for wounded soldiers, with the terrain being torn up by shells and explosions the ambulance at times would overturn further harming its passengers. it was obvious that the ambulance system needed work for both the union and the confederate armies, yet only the union would fully prosper in this area with the help of dr. jonathan letterman and the beginning stages of the ambulance corps. letterman's revolutionary ideas dramatically improved both the ambulance and the ambulance system. with new designs the common union ambulance was now composed of a 750 lb wagon that was powered by 2–4 horses and was made to carry 2–6 wounded soldiers. other accessories that were standard for the improved ambulances included compartments to store medical supplies, stretchers, water, and even removable benches and seats to adapt to the number of passengers. letterman's ideas improved the ambulance system dramatically by setting standards to train the ambulance crew, by having routine ambulance inspections, and also by developing strategical evacuation plans to most efficiently save and transport fallen soldiers. letterman's system was so efficient that all wounded soldiers at the battle of antietam were removed from the battlefield and sent to care within one day so this new system saved thousands of union lives. soon after the battle of antietam began the formation of the ambulance corps and while the confederates were also working out a similar system their constant shortage of ambulances was not adequate enough to summon such an effective force as even some their ambulances came by capturing union ambulances. soldiers period painting of an american civil war soldier, wounded by a minié ball, lies in bed with a gangrenous amputated arm. the most common battlefield injury was being wounded by enemy fire. unless the wounds were minor, this often led to amputation of limbs to prevent infection from setting in, as antibiotics had not yet been discovered. amputations had to be made at the point above where the wound occurred, often leaving men with stub limbs. a flap of skin was saved, and stitched to the stump to cover the wound. there were two types of amputations, primary and secondary. the primary amputation was done between 24 and 48 hours after the injury. the secondary amputation was done after a longer period of time, often because of infection. during this time, there were two main methods of amputation, the flap method and circular method. the flap method was typically used when an amputation had to be done quickly. the bone was cut above flaps of skin and muscle, which were pulled together to close the wound. the circular method was a circular cut that only allowed a flap of surface skin to cover the wound. the flap method was more likely than the circular method to lead to gangrene, as the deep muscle tissue suffered from lack of circulation. approximately 30,000 amputations were performed during the civil war. patients were generally sedated prior to a surgical operation. the use of ether as general anesthesia started in 1846 and the use of chloroform in 1847. contrary to popular belief, few soldiers experienced amputation without any anesthetic. a post-war review by the u.s. army medical department found that over 99.6% of surgeries performed by their staff were conducted under some form of general anesthesia. surgeons preferred chloroform in field hospitals, while ether was more common relegated to general hospitals well beyond the range of fighting due to its explosive nature. the most popular anesthetic agent was chloroform, accounting for more than 70% of all surgeries in the north according to a study in the medical and surgical history of the war of the rebellion. ether was more commonly used behind the lines because it required a heavier dosage, took longer to induce insensibility, and was highly flammable. in some cases, a blend of ether and chloroform was used to sedate patients. when properly done, the patient would feel no pain during their surgery, but there was no structured system like the modern phases of anesthesia for gauging the proper dosage and depth of a patient's amnesia, analgesia, and muscle relaxation. in some cases, patients were insensible to pain, but did not experience amnesia. stonewall jackson, for example, recalled the sound of the saw cutting through the bone of his arm, but recalled no pain. infection was the most common cause of death of injured soldiers. infection occurred for a variety of reasons. surgeons would typically go from surgery to surgery without cleaning their equipment or their hands; surgeons would use sponges that they only rinsed in water on multiple patients. these practices caused bacteria to spread from patient to patient, from all surgical surfaces, and from the environment, which caused infections in many. it has been said that the american civil war was the first "modern war" in terms of technology and lethality of weapons, but that it was simultaneously fought "at the very end of the medical 'middle ages.'" very little was known about the causes of disease, and so a minor wound could easily become infected and take a life. battlefield surgeons were underqualified and hospitals were generally poorly supplied and staffed. in fact, there were so many wounded and not enough doctors, so doctors were forced to spend only a little time with each patient. they became proficient at quick care. some surgeons spent as little as 10 minutes on amputating a limb. the most common battlefield operation was amputation. if a soldier was badly wounded in the arm or leg, amputation was usually the only solution. about 75% of amputees survived the operation. a 2016 research paper found that civil war surgery was effective at improving patient health outcomes. the study finds that "in many cases amounted to a doubling of the odds of survival". if a wound produced pus, it was thought that it meant the wound was healing, when in fact it meant the injury was infected. specifically, if the pus was white and thick, the doctors thought it was a good sign. roughly three in five union casualties and two in three confederate casualties died of disease. women as nurses north and south, over 20,000 women volunteered to work in hospitals, usually in nursing care. they assisted surgeons during procedures, gave medicines, supervised the feedings and cleaned the bedding and clothes. they gave a good cheer, wrote letters the men dictated, and comforted the dying. the sanitary commission handled most of the nursing care of the union armies, together with the necessary acquisition and transportation of medical supplies. dorothea dix, serving as the commission's superintendent, was able to convince the medical corps of the value of women working in 350 commission or army hospitals. a representative nurse was helen l. gilson (1835–68) of chelsea, massachusetts, who served in the sanitary commission. she supervised supplies, dressed wounds, and cook special foods for patients on a limited diet. she worked in hospitals after antietam, fredericksburg, chancellorsville, and gettysburg battles. she was a successful administrator, especially at the hospital for black soldiers at city point, virginia. the middle-class women north and south who volunteered provided vitally needed nursing services and were rewarded with a sense of patriotism and civic duty in addition to the opportunity to demonstrate their skills and gain new ones, while receiving wages and sharing the hardships of the men. mary livermore, mary ann bickerdyke, and annie wittenmeyer played leadership roles. after the war some nurses wrote memoirs of their experiences; examples include dix, livermore, sarah palmer young, and sarah emma edmonds. several thousand women were just as active in nursing in the confederacy, but were less well organized and faced severe shortages of supplies and a much weaker system of 150 hospitals. nursing and vital support services were provided not only by matrons and nurses, but also by local volunteers, slaves, free blacks, and prisoners of war. freed slaves and civilians historian leon litwack has noted, "neither white nor black southerners were unaffected by the physical and emotional demands of the war. scarcities of food and clothing, for example, imposed hardships on both races." conditions were worse for blacks. late in the war and soon after large numbers of blacks moved away from the plantation. the freedmen's bureau refugee camps saw infectious disease such as smallpox reach epidemic proportions. jim downs states: disease and sickness had more devastating and fatal effects on emancipated slaves than on soldiers, since ex-slaves often lacked the basic necessities to survive. emancipation liberated bondspeople from slavery, but they often lacked clean clothing, adequate shelter, proper food, and access to medicine in their escape toward union lines. many free slaves died once they secured refuge behind union camps aftermath based on their experiences in the war, many veterans went on to develop high standards for medical care and new medicines. the modern pharmaceutical industry began developing in the decades after the war. colonel eli lilly had been a pharmacist; he built a pharmaceutical empire after the war. clara barton founded the american red cross to provide civilian nursing services in wartime.