THE RUDOLF REPORT

8. EVALUATION OF CHEMICAL ANALYSESside of the exterior walls, there is no recognizable concentration profile.The reason for this may be that the dry walls allow the hydrogencyanide to diffuse more easily into the masonry, while the hydrogencyanide more readily reacts superficially on the moist exterior walls. Itis more probable, however, that no migration of soluble cyanide saltsto the surface took place in the interior wall due to dryness. Thesesamples are also interesting insofar as they prove that high quantitiesof cyanide compounds, highly-resistant for long periods of time, canform on warm and dry interior walls. Due to the high ground watertable in Birkenau, as well as due to the lack of an effective heat insulation,the exterior walls must be expected to have been quite cool andmoist even when the interior was heated, particularly during the coolseasons.The samples from the walls added during the conversion to hot airdisinfestation should exhibit no cyanide residues. Accordingly, sampleno. 10 from the interior wall incorporated at a later time exhibits only avery low cyanide concentration near the detectable threshold. Sample21 was taken from the mortar between the bricks of the wall installedlater, at a depth of 1 cm to 5 cm into the masonry. There is a crack inthe masonry of the interior wall at this location. The analysis showsminimal but hardly interpretable traces of cyanide below the detectablethreshold in this interior wall as well. This finding may indicate disinfestationof these rooms after the conversion to hot disinfestation, if theslight quantities have not in any case lost all probative value, like thecontrol analysis of the other samples have shown.Sample 18, finally, was taken from the door frame which was onlyincorporated after the conversion to hot air disinfestation. Below thelower hinge, the wood exhibits a visibly blue pigmentation (see Fig.70, p. 261). The pigment was able to form here due to the moisture inthe floor, in connection with the rusting iron. This is assuming that therooms were either charged with hydrogen cyanide after the conversionof the installation or that the floor of the installation continued to giveoff cyanide over longer periods of time. In the first case, the cyanidetraces in the walls added later (Samples 10 and 21) could actually beexplained by fumigation of the rooms. However, during the conversionof this wing to a hot air disinfestation facility, this gas-tight door mayhave been removed from the access way to this wing and re-used here,so that the cyanide would result from earlier fumigations. The analyticalresults should only be conditionally considered as qualitative, since263