children's brains were preserved in jars of formaldehyde and stored in the basement of the clinic and in the private collection of heinrich gross, one of the institution's directors, until 2001. when the second world war began in september 1939, less rigorous standards of assessment and a quicker approval process were adopted. older children and adolescents were included and the conditions covered came to include ... various borderline or limited impairments in children of different ages, culminating in the killing of those designated as juvenile delinquents. jewish children could be placed in the net primarily because they were jewish; and at one of the institutions, a special department was set up for 'minor jewish-aryan half-breeds'.— lifton more pressure was placed on parents to agree to their children being sent away. many parents suspected what was happening and refused consent, especially when it became apparent that institutions for children with disabilities were being systematically cleared of their charges. the parents were warned that they could lose custody of all their children and if that did not suffice, the parents could be threatened with call-up for 'labour duty'. by 1941, more than 5,000 children had been killed. the last child to be killed under aktion t4 was richard jenne on 29 may 1945, in the children's ward of the kaufbeuren-irsee state hospital in bavaria, germany, more than three weeks after us army troops had occupied the town. killing of adults invasion of poland ss-gruppenführer leonardo conti brandt and bouhler developed plans to expand the programme of euthanasia to adults. in july 1939 they held a meeting attended by conti and professor werner heyde, head of the ss medical department. this meeting agreed to arrange a national register of all institutionalised people with mental illnesses or physical disabilities. the first adults with disabilities to be killed en masse by the nazi regime were poles. after the invasion on 1 september 1939, adults with disabilities were shot by the ss men of einsatzkommando 16, selbstschutz and ek-einmann under the command of ss-sturmbannführer rudolf tröger, with overall command by reinhard heydrich, during the genocidal operation tannenberg. all hospitals and mental asylums of the wartheland were emptied. the region was incorporated into germany and earmarked for resettlement by volksdeutsche following the german conquest of poland. in the danzig (now gdańsk) area, some 7,000 polish patients of various institutions were shot and 10,000 were killed in the gdynia area. similar measures were taken in other areas of poland destined for incorporation into germany. the first experiments with the gassing of patients were conducted in october 1939 at fort vii in posen (occupied poznań), where hundreds of prisoners were killed by means of carbon monoxide poisoning, in an improvised gas chamber developed by albert widmann, chief chemist of the german criminal police (kripo). in december 1939, reichsführer-ss heinrich himmler witnessed one of these gassings, ensuring that this invention would later be put to much wider uses. bunker no. 17 in artillery wall of fort vii in poznań, used as improvised gas chamber for early experiments the idea of killing adult mental patients soon spread from occupied poland to adjoining areas of germany, probably because nazi party and ss officers in these areas were most familiar with what was happening in poland. these were also the areas where germans wounded from the polish campaign were expected to be accommodated, which created a demand for hospital space. the gauleiter of pomerania, franz schwede-coburg, sent 1,400 patients from five pomeranian hospitals to undisclosed locations in occupied poland, where they were shot. the gauleiter of east prussia, erich koch, had 1,600 patients killed out of sight. more than 8,000 germans were killed in this initial wave of killings carried out on the orders of local officials, although himmler certainly knew and approved of them. the legal basis for the programme was a 1939 letter from hitler, not a formal "führer's decree" with the force of law. hitler bypassed conti, the health minister and his department, who might have raised questions about the legality of the programme and entrusted it to bouhler and brandt. reich leader bouhler and dr. brandt are entrusted with the responsibility of extending the authority of physicians, to be designated by name, so that patients who, after a most critical diagnosis, on the basis of human judgment , are considered incurable, can be granted mercy death .— adolf hitler, 1 september 1939 the killings were administered by viktor brack and his staff from tiergartenstraße 4, disguised as the "charitable foundation for cure and institutional care" offices which served as the front and was supervised by bouhler and brandt. the officials in charge included herbert linden, who had been involved in the child killing programme; ernst-robert grawitz, chief physician of the ss and august becker, an ss chemist. the officials selected the doctors who were to carry out the operational part of the programme; based on political reliability as long-term nazis, professional reputation and sympathy for radical eugenics. the list included physicians who had proved their worth in the child-killing programme, such as unger, heinze and hermann pfannmüller. the recruits were mostly psychiatrists, notably professor carl schneider of heidelberg, professor max de crinis of berlin and professor paul nitsche from the sonnenstein state institution. heyde became the operational leader of the programme, succeeded later by nitsche. listing of targets from hospital records hartheim euthanasia centre, where over 18,000 people were killed. in early october, all hospitals, nursing homes, old-age homes and sanatoria were required to report all patients who had been institutionalised for five years or more, who had been committed as "criminally insane", who were of "non-aryan race" or who had been diagnosed with any on a list of conditions. the conditions included schizophrenia, epilepsy, huntington's chorea, advanced syphilis, senile dementia, paralysis, encephalitis and "terminal neurological conditions generally". many doctors and administrators assumed that the reports were to identify inmates who were capable of being drafted for "labour service" and tended to overstate the degree of incapacity of their patients, to protect them from labour conscription. when some institutions refused to co-operate, teams of t4 doctors (or nazi medical students) visited and compiled the lists, sometimes in a haphazard and ideologically motivated way. during 1940, all jewish patients were removed from institutions and killed. as with child inmates, adults were assessed by a panel of experts, working at the tiergartenstraße offices. the experts were required to make their judgements on the reports, not medical histories or examinations. sometimes they dealt with hundreds of reports at a time. on each they marked a + (death), a - (life), or occasionally a ? meaning that they were unable to decide. three "death" verdicts condemned the person and as with reviews of children, the process became less rigorous, the range of conditions considered "unsustainable" grew broader and zealous nazis further down the chain of command increasingly made decisions on their own initiative. gassing the first gassings in germany proper took place in january 1940 at the brandenburg euthanasia centre. the operation was headed by brack, who said "the needle belongs in the hand of the doctor". bottled pure carbon monoxide gas was used. at trials, brandt described the process as a "major advance in medical history". once the efficacy of the method was confirmed, it became standard and was instituted at a number of centres in germany under the supervision of widmann, becker and christian wirth – a kripo officer who later played a prominent role in the final solution (extermination of jews) as commandant of newly built death camps in occupied poland. in addition to brandenburg, the killing centres included grafeneck castle in baden-württemberg (10,824 dead), schloss hartheim near linz in austria (over 18,000 dead), sonnenstein in saxony (15,000 dead), bernburg in saxony-anhalt and hadamar in hesse (14,494 dead). the same facilities were also used to kill mentally sound prisoners transferred from concentration camps in germany, austria and occupied parts of poland. bishop jan maria michał kowalski, killed at hartheim condemned patients were transferred from their institutions to new centres in t4 charitable ambulance buses, called the community patients transports service. they were run by teams of ss men wearing white coats, to give it an air of medical care. to prevent the families and doctors of the patients from tracing them, the patients were often first sent to transit centres in major hospitals, where they were supposedly assessed. they were moved again to special treatment (sonderbehandlung) centres. families were sent letters explaining that owing to wartime regulations, it was not possible for them to visit relatives in these centres. most of these patients were killed within 24 hours of arriving at the centres and their bodies cremated. for every person killed, a death certificate was prepared, giving a false but plausible cause of death. this was sent to the family along with an urn of ashes (random ashes, since the victims were cremated en masse). the preparation of thousands of falsified death certificates took up most of the working day of the doctors who operated the centres. during 1940, the centres at brandenburg, grafeneck and hartheim killed nearly 10,000 people each, while another 6,000 were killed at sonnenstein. in all, about 35,000 people were killed in t4 operations that year. operations at brandenburg and grafeneck were wound up at the end of the year, partly because the areas they served had been cleared and partly because of public opposition. in 1941, however, the centres at bernburg and sonnenstein increased their operations, while hartheim (where wirth and franz stangl were successively commandants) continued as before. another 35,000 people were killed before august 1941, when the t4 programme was officially shut down by hitler. even after that date the centres continued to be used to kill concentration camp inmates: eventually some 20,000 people in this category were killed. in 1971, gitta sereny conducted interviews with stangl, who was in prison in düsseldorf, after having been convicted of co-responsibility for killing 900,000 people, while commandant of the sobibor and treblinka extermination camps in poland. stangl gave sereny a detailed account of the operations of the t4 programme based on his time as commandant of the killing facility at the hartheim institute. he described how the inmates of various asylums were removed and transported by bus to hartheim. some were in no mental state to know what was happening to them but many were perfectly sane and for them various forms of deception were used. they were told they were at a special clinic where they would receive improved treatment and were given a brief medical examination on arrival. they were induced to enter what appeared to be a shower block, where they were gassed with carbon monoxide (the ruse was also used at extermination camps). number of euthanasia victims the ss functionaries and hospital staff associated with aktion t4 in the german reich were paid from the central office at tiergartenstraße 4 in berlin from the spring of 1940. the ss and police from ss-sonderkommando lange responsible for murdering the majority of patients in the annexed territories of poland since october 1939, took their salaries from the normal police fund, supervised by the administration of the newly formed wartheland district; the programme in germany and occupied poland was overseen by heinrich himmler. before 2013, it was believed that 70,000 persons were murdered in the euthanasia programme, but the german federal archives reported that research in the archives of former east germany indicated that the number of victims in germany and austria from 1939 to 1945 was about 200,000 persons and that another 100,000 persons were victims in other european countries. in the german t4 centres there was at least the semblance of legality in keeping records and writing letters. in polish psychiatric hospitals no one was left behind. killings were inflicted using gas-vans, sealed army bunkers and machine guns; families were not informed about the murdered relatives and the empty wards were handed over to the ss. victims of aktion t4 (official data from 1985), 1940 – september 1941 t4 centeroperation timetablenumber of victims fromuntil (officially and unofficially)19401941total grafeneck20 january 1940december 19409,839—9,839 brandenburg8 february 1940october 19409,772—9,772 bernburg21 november 194030 july 1943—8,6018,601 hartheim6 may 1940december 19449,6708,59918,269 sonnensteinjune 1940september 19425,9437,77713,720 hadamarjanuary 194131 july 1942—10,07210,072 total by year 35,22435,04970,273 territories of occupied poland hospitalregionextermination