Neighbours of Mueller apparently told Doughty that when the Baron lay unconscious large quantities of boxes and packages were put out of the back windows, where there were people ready to receive them. What was taken and what, if anything, was recovered, is not known. A second assault on Mueller's papers apparently took place in the 1930s under the directorship of one of Mueller's successors at the National Herbarium and Royal Botanic Gardens, F.J. Raye. The fires were said to have burned for days. It is difficult to comprehend such an act, and if it did happen it must surely go down in our history as one of the most wanton destructions of historic records.
Further research is needed into the matter.
The Mueller project has access to about 10,000 Mueller letters. Just what proportion this represents of the original total of Mueller letters is not easy to determine. The final totals hardly seem conceivable - several hundreds of thousands. Perhaps we need look no further for an explanation of Potter's failure to write Mueller's biography. Both authors faced the problem of trying to recover surviving information about Mueller which is now scattered around the world.