A pathologist secretly ordered the removal of organs from dead children and kept the body parts in a filthy cellar, a medical tribunal has heard.
Dr van Velzen failed to turn up for the hearing
Some organs had deteriorated as they had been retained for so long, and pot labels were wearing off due to damp.
Professor Dick van Velzen, 55, worked at Liverpool's Alder Hey Children's Hospital at the height of the organ retention scandal from 1988 to 1994.
He has failed to appear before a General Medical Council (GMC) panel.
Prof van Velzen, from Oegstgeest in Holland, is accused of carrying out post mortem examinations and keeping children's organs without their parents' consent, during his six years in the hospital's pathology department.
He is charged with serious professional misconduct, but has chosen not to attend the GMC's Fitness to Practice hearing in Manchester nor send any legal representation on his behalf.
The GMC panel heard that staff at Alder Hey had to abandon care of the jars, of which there were up to 3,500, because it was "too big a task".
Giving evidence at the hearing on Wednesday, Paul Dearlove, a former laboratory officer at Alder Hey which included the now closed site in Myrtle Street , said virtually nothing was disposed of from Prof van Velzen's post mortem examinations.
Mr Dearlove said: "He gave instructions that nothing was to be thrown away when he had finished with a post mortem.
"Within a few weeks pots were building up in the cellar of the lab on Myrtle Street."
Mr Dearlove told the GMC that most of the jars contained organs from about 1,000 patients, while others contained whole foetuses brought in from the local women's hospital.
He said: "The cellar was filthy and there was so much material in some of the pots that it was in quite a bad condition.
"It was damp down there so the labels came off on a few of them.
"Some of the material was kept in pots with plastic lids and the formula in one or two of them dried out, which meant the samples deteriorated rapidly."
He added: "In the end we had to abandon care of the pots because it was just too big a task."
The panel heard that Prof van Velzen reported on only around 10% of the post mortem examinations he carried out.
Mr Dearlove said this left the laboratory staff with "a terrific backlog of work".
If found guilty of professional misconduct, Prof van Velzen could face a ban from practising.
The tribunal continues.