Kremer was born in Stellberg. He was a doctor of medicine as well as philosophy he also studied natural science and mathematics. He studied in Heidelberg, Strassburg as well as Berlin; he received his medical degree in 1919 and his philosophy degree in 1914. He was the "assistant surgeon at the surgical clinic of the University, Charité, the ward of internal diseases of the Municipal Hospital Berlin-Neukölln, the surgical clinic of the University of Cologne and prosector in the Institutes of Anatomy in Bonn and Münster. He became Dozent of anatomy in 1929 and was promoted there in 1936 to be professor in commission. At the same time he was commissioned to lecture on the science of human hereditariness ." He also did some writing, he mentions two articles that he wrote in the diary he kept, the first being "Inherited or Acquired? A Noteworthy Contribution to the Problem of Hereditariness of Traumatic Deformations" and the second titled "New Elements of Cell and Tissues Investigations".
Medical experiments
The main priority of SS doctors at concentration camps throughout Nazi-occupied Europe was not to provide basic medical services to prisoners, but rather to give the appearance of competent medical care. Following the full-scale implementation of the Final Solution, much of their time was occupied with concentration camp exterminations, sorting/selection of the newly-arrived prisoners to research methods to improve the health and survivability of soldiers; 2) to lay the groundwork for post-war scientific research; and 3) to carry out the dictates of the racial policies of the Nazi Party. Some experiments were also done at the behest of pharmaceutical companies and medical institutes, for the doctors' own research interests, and to benefit the doctors' personal careers. Kremer was particularly interested in the effects of starvation on the human body, especially on the liver, and because Kremer was responsible for examining the prisoners that sought admission to the camp infirmary, he was able to personally select the prisoners that he believed would make good test subjects for his experiments. He often performed autopsies in order to extract samples from the liver, spleen and pancreas. On several occasions in his diary, he mentions the extraction of organs and tissues from living victims, such as on October 15, 1942, when he writes, "Living-fresh material of liver, spleen and pancreas taken from an abnormal individual." Kremer's diary contains descriptions of at least five more similar instances. At his hearing on July 30, 1947, Kremer stated that "I observed the prisoners in this group carefully and whenever one of them particularly interested me because of his advanced stage of starvation, I ordered the medical orderly to reserve him and to inform me when this patient would be killed by injection."
Special actions
All SS doctors were required to be present at what were called "special actions", which was when the mass gassings took place. The most common victims were children, the elderly, mothers with young children and any others considered unfit to work. During his trial, Kremer described how a gassing was conducted and what his role as doctor was. The gassings were conducted in cabins located on the outskirts of the camp; the victims were transported by railway, and after they arrived, prisoners "were first driven to barracks where the victims undressed and then went naked to the gas chambers. Very often no incidents occurred, as the SS men kept people quiet, maintaining that they were to bathe and be deloused. After driving all of them into the gas chamber the door was closed and an SS man in a gas mask threw the contents of a Cyclon tin through an opening in the side wall." Kremer's role was to sit in a van along with a medical orderly ready to treat any officers that might succumb to the gas.
Executions and beatings
Throughout Kremer's diary there are multiple occasions where he mentions being in attendance at various executions and beatings. At least four instances can be found where he mentions executions either by gun, phenol injection, or an unspecified method. He mentions briefly no fewer than three instances where he oversaw the punishment of prisoners. The physicians were required to examine the victim before the punishment and to remain during the administration of punishment; in practice however, physicians rarely, if ever, examined victims and did not openly object to the punishments.
Testimony and indictment
Johann Kremer was tried in the Auschwitz trials at the sitting of the Supreme Court National Tribune in Kraków throughout November and December 1947. Based on the contents of his diary and his own confessions, Kremer participated in fourteen gassings as well as multiple public executions and special actions, also known as gassings. During his testimony, he described the process by which he selected his victims, the process of gaining the necessary information for his research, and he states that "after I had been given this information a medical orderly would come and kill the patient with an injection in the heart area. To my knowledge all these patients were killed with phenol injections. The patient died immediately after being given such an injection. I myself never administered fatal injections."
